When you ask the bank why they close your account, whether their answer? In my opinion there is only one reason why the bank closed the account of the person, ie since the bank go bankrupt. In my country there ever bank that went bankrupt and closed more than 1 million accounts of customers and amount to trillions. I personally still believe the bank because I am sure the bank that I chose is a bona fide bank. You can sue him in court if you do not make mistakes that lead to your account closed.
In this case the account is closed and the bank is still operational. I think Op is hiding something.
As far as I know bank cannot freeze or close your account unless there is a court order. About balances being drained, there is a fee using their service to store your money. So don't surprise if in the long run your account balance become negative
I think it largely depends on jurisdiction
On the other hand, does PayPal need a court order to freeze someone's account? Judging by the number of people thinking of this service as scam operators, they don't need any such order altogether to lock or freeze an account. I guess with banks it is pretty much along the same line. If they think that someone is, for example, laundering money, they could just suspend all activity associated with that account on their own without prior notice until they themselves or special agencies investigate the issue