If you opened your bank account long time ago they will not just close your account. You had to make sure before 1st of may I believe, that the name of your Thai phone number matches the phone number in your bank account. Maybe people did not take care of that.
According to the Facebook page of the Bangkok Community Help Foundation, Bangkok Bank has reportedly begun freezing accounts and blocking the cards of Russian nationals who fail to meet the new eligibility criteria.
My Bangkok bank still works fine, and I’m not even in Thailand. I was reading something about they wanted to freeze accounts of russian people. Plus maybe you need to have your telephone number under the same name as your bank account and updated it in your settings of the bank app
That rules have changed a bit since a few months. It’s more difficult to get a Thai bank account if your are not a resident in Thailand. Not even agents can help.