Cancellation of subscription broken / Ask question form part

Expected behavior Cancellation of subscription works. (I am referring to this page: https://mdbootstrap.com/profile/cancel-subscription/)

Actual behavior Cancellation of subscription is impossible. The modals on the page seem to be broken. No actions ecept the back button are possible. The console log shows the following (I replaced personal information from the URL params for privacy reasons):

<span class="pln">    </span><span class="typ">Uncaught</span><span class="pln"> </span><span class="typ">TypeError</span><span class="pun">:</span><span class="pln"> </span><span class="kwd">this</span><span class="pun">.</span><span class="pln">_config </span><span class="kwd">is</span><span class="pln"> </span><span class="kwd">undefined</span><span class="pln">
    _initializeBackDrop https</span><span class="pun">:</span><span class="com">//mdbcdn.b-cdn.net/wp-content/themes/mdbootstrap4/docs-app/js/mdb5/standard/compiled.min.js?ver=7.1.0-update.4:339</span><span class="pln">
    ob https</span><span class="pun">:</span><span class="com">//mdbcdn.b-cdn.net/wp-content/themes/mdbootstrap4/docs-app/js/mdb5/standard/compiled.min.js?ver=7.1.0-update.4:339</span><span class="pln">
    pa https</span><span class="pun">:</span><span class="com">//mdbcdn.b-cdn.net/wp-content/themes/mdbootstrap4/docs-app/js/mdb5/standard/compiled.min.js?ver=7.1.0-update.4:339</span><span class="pln">
    getOrCreateInstance https</span><span class="pun">:</span><span class="com">//mdbcdn.b-cdn.net/wp-content/themes/mdbootstrap4/docs-app/js/mdb5/standard/compiled.min.js?ver=7.1.0-update.4:36</span><span class="pln">
    callback https</span><span class="pun">:</span><span class="com">//mdbcdn.b-cdn.net/wp-content/themes/mdbootstrap4/docs-app/js/mdb5/standard/compiled.min.js?ver=7.1.0-update.4:369</span><span class="pln">
    callback https</span><span class="pun">:</span><span class="com">//mdbcdn.b-cdn.net/wp-content/themes/mdbootstrap4/docs-app/js/mdb5/standard/compiled.min.js?ver=7.1.0-update.4:369</span><span class="pln">
    </span><span class="typ">Hh</span><span class="pln"> https</span><span class="pun">:</span><span class="com">//mdbcdn.b-cdn.net/wp-content/themes/mdbootstrap4/docs-app/js/mdb5/standard/compiled.min.js?ver=7.1.0-update.4:36</span><span class="pln">
    </span><span class="typ">Nb</span><span class="pln"> https</span><span class="pun">:</span><span class="com">//mdbcdn.b-cdn.net/wp-content/themes/mdbootstrap4/docs-app/js/mdb5/standard/compiled.min.js?ver=7.1.0-update.4:36</span><span class="pln">
    </span><span class="typ">Nb</span><span class="pln"> https</span><span class="pun">:</span><span class="com">//mdbcdn.b-cdn.net/wp-content/themes/mdbootstrap4/docs-app/js/mdb5/standard/compiled.min.js?ver=7.1.0-update.4:36</span><span class="pln">
    </span><span class="typ">Nb</span><span class="pln"> https</span><span class="pun">:</span><span class="com">//mdbcdn.b-cdn.net/wp-content/themes/mdbootstrap4/docs-app/js/mdb5/standard/compiled.min.js?ver=7.1.0-update.4:36</span><span class="pln">
    </span><span class="str"><anonymous></span><span class="pln"> https</span><span class="pun">:</span><span class="com">//mdbcdn.b-cdn.net/wp-content/themes/mdbootstrap4/docs-app/js/mdb5/standard/compiled.min.js?ver=7.1.0-update.4:369</span><span class="pln">
    </span><span class="str"><anonymous></span><span class="pln"> https</span><span class="pun">:</span><span class="com">//mdbcdn.b-cdn.net/wp-content/themes/mdbootstrap4/docs-app/js/mdb5/standard/compiled.min.js?ver=7.1.0-update.4:19</span><span class="pln">
    </span><span class="str"><anonymous></span><span class="pln"> https</span><span class="pun">:</span><span class="com">//mdbcdn.b-cdn.net/wp-content/themes/mdbootstrap4/docs-app/js/mdb5/standard/compiled.min.js?ver=7.1.0-update.4:19</span><span class="pln">
compiled</span><span class="pun">.</span><span class="pln">min</span><span class="pun">.</span><span class="pln">js</span><span class="pun">:</span><span class="lit">339</span><span class="pun">:</span><span class="lit">11757</span><span class="pln">
</span><span class="typ">Uncaught</span><span class="pln"> </span><span class="typ">ReferenceError</span><span class="pun">:</span><span class="pln"> mdb </span><span class="kwd">is</span><span class="pln"> </span><span class="kwd">not</span><span class="pln"> </span><span class="kwd">defined</span><span class="pln">
    </span><span class="str"><anonymous></span><span class="pln"> https</span><span class="pun">:</span><span class="com">//mdbcdn.b-cdn.net/wp-content/themes/mdbootstrap4/js/new-mdb/mdb-cancel-subscription.js?ver=4.20.0-update.3:355</span><span class="pln">
    </span><span class="str"><anonymous></span><span class="pln"> https</span><span class="pun">:</span><span class="com">//mdbcdn.b-cdn.net/wp-content/themes/mdbootstrap4/js/new-mdb/mdb-cancel-subscription.js?ver=4.20.0-update.3:357</span><span class="pln">
mdb</span><span class="pun">-</span><span class="pln">cancel</span><span class="pun">-</span><span class="pln">subscription</span><span class="pun">.</span><span class="pln">js</span><span class="pun">:</span><span class="lit">355</span><span class="pun">:</span><span class="lit">30</span><span class="pln">
</span><span class="typ">Uncaught</span><span class="pln"> </span><span class="typ">ReferenceError</span><span class="pun">:</span><span class="pln"> mdb </span><span class="kwd">is</span><span class="pln"> </span><span class="kwd">not</span><span class="pln"> </span><span class="kwd">defined</span><span class="pln">
    </span><span class="str"><anonymous></span><span class="pln"> https</span><span class="pun">:</span><span class="com">//mdbootstrap.com/profile/cancel-subscription/?...</span><span class="pln">
cancel</span><span class="pun">-</span><span class="pln">subscription</span><span class="pun">:</span><span class="lit">982</span><span class="pun">:</span><span class="lit">20</span><span class="pln">
</span><span class="typ">Uncaught</span><span class="pln"> </span><span class="typ">ReferenceError</span><span class="pun">:</span><span class="pln"> mdb </span><span class="kwd">is</span><span class="pln"> </span><span class="kwd">not</span><span class="pln"> </span><span class="kwd">defined</span><span class="pln">
    onload https</span><span class="pun">:</span><span class="com">//mdbootstrap.com/profile/cancel-subscription/?...</span><span class="pln">
cancel</span><span class="pun">-</span><span class="pln">subscription</span><span class="pun">:</span><span class="lit">895</span><span class="pun">:</span><span class="lit">23</span><span class="pln">
</span><span class="typ">Uncaught</span><span class="pln"> </span><span class="pun">(</span><span class="kwd">in</span><span class="pln"> promise</span><span class="pun">)</span><span class="pln"> </span><span class="typ">ReferenceError</span><span class="pun">:</span><span class="pln"> mdb </span><span class="kwd">is</span><span class="pln"> </span><span class="kwd">not</span><span class="pln"> </span><span class="kwd">defined</span><span class="pln">
    b https</span><span class="pun">:</span><span class="com">//mdbcdn.b-cdn.net/wp-content/themes/mdbootstrap4/docs-app/js/dist/search/search.min.js?ver=1.1.0:1</span><span class="pln">
search</span><span class="pun">.</span><span class="pln">min</span><span class="pun">.</span><span class="pln">js</span><span class="pun">:</span><span class="lit">1</span><span class="pun">:</span><span class="lit">978</span>

Addendum: I feel like this form is not the right one to use, am I correct? Nevertheless is the form also broken in some way, because if I select TWE as my technology in the inputbox, the inputbox for MDB version is disabled (which is presumably correct behaviour). However, the checker of the form requires a MDB-Version to be set and therefore it is impossible to fill ou this form with technology=TW-Elements, which would be more correct in my case. But then again I am not really having an issue with the product itself only with the way it is sold / how the subscription works. Where else should I report this?