Whats the reason for suspending the account, what did they say?
Just the sae question i was abiut to ask, what i can deduce from the op's statement is the fact that he may have been involved in some money laundering activities that have led to the stake asking him for such legal documents as proof of funds.
It could be huge deposits that he can't justify from which source it came and the stake is looking for a legitimate source that's not related to crypto.
And if that's not acceptable to them, OP has got no choice but just to leave it since he has already asked and contested about it. There's no way to change that decision from them. You can still gamble with other casinos if you want to OP but, there might be some really huge thing as to why they've banned your account related to your deposits/withdrawals.