Unfortunately, this is subject to happen at any time since most centralized services claim in their TOS that they have every right to close your account without having to provide you with a valid reason.
I can find this right to close an account if the user does not agree to the E-sign agreement.
You may withdraw your consent to receive Communications electronically by contacting us at
https://help.coinbase.com. If you fail to provide or if you withdraw your consent to receive Communications electronically, Coinbase reserves the right to immediately close your Coinbase Account or charge you additional fees for paper copies.
Source:
https://www.coinbase.com/legal/user_agreement/united_statesBut you can find more details on their user agreement for other countries such as:
We may suspend, restrict, or terminate your access to any or all of the Coinbase Services and/or deactivate or cancel your Coinbase Account, without reason by giving you two months’ notice. You acknowledge that our decision to take certain actions, including limiting access to, suspending, or closing your Coinbase Account, may be based on confidential criteria that are essential for the purposes of our risk management and security protocols. You agree that Coinbase is under no obligation to disclose the details of its risk management and security procedures to you.
Source:
https://www.coinbase.com/legal/user_agreement/payments_europeBased on that statement, I do agree that even if you ask publicly, they won't reply to you, if they ever do it at all. To put it simply, Coinbase might consider OP accounts to have some risk if they continue to allow him to use their exchange, whatever that is. I'd not stress too much and simply move on if that were the case OP, try to find other exchanges or start using DEX to avoid being ditched by an exchange again. Do correct me if I'm wrong.