There's provably a reason on why you have been restricted on their chat. Since there's no person in right mind would do that. Maybe you are spamming or done something wrong which you didn't notice. Since the manager you mentioned is already got fired then maybe the least you can do is to contact their support and talk about your restriction. Provably you can get a proper solution on your issue and the existing managers might grant your request.

Also maybe it will take time for you to get a response if you rely only in their thread. Since I think they are not so active her, so much better just reach their support since I think that is the fastest way you can solve your concerns.