Banning you from the chat isn't ok, but if you wrote there too much stuff complaining about your situation it could've been considered as spamming. But that's not the worst thing here, why the hell aren't they returning your emails and aren't resolving this?

I have a question to ask, though. It the letter Stake.com accused you of having multiple accounts, did they have any grounds to assume so?

Because you may be a great customer, placed huge bets, but that doesn't dispense you from obliging to such basic rules. Maybe a while ago you created an account, but then forgot and created a new one? Casinos check this kind of stuff whenever there are big wins, you must understand that...