As in, a real legal demand with a complaint attached that is addressed to their counsel and includes estimates of monetary damages and alludes (not threatens) to the specific jurisdiction and court it would be submitted to for adjudication.
Send copies of this letter, by registered/certified mail, to several contacts.
They will have to respond to this and these responses will be expensive.
If you are in the right - even marginally so - your account will get fixed because it will be much too expensive to continue to ignore you.
Filling in web forms and emailing form addresses costs google nothing. It makes perfect sense that these actions (appear) to have identical results as doing nothing.