FNB blocked account and threatened to tremninate relationship

I sold bitcoin and received payment into my FNB account. the buyer then went to the bank and claimed that I did not release his bitcoin and as a consequence my account got blocked. i mailed all the supporting documents that proofed my side to the bank, but still no answer from them. this was the sequence of events 11/11/2023 - account blocked 12/11/2023 - Fnb mailed to request documents 14/11/2023 - sent documents and affidavit to Fnb 15/11/2023 - mailed to ask for feedback 20/11/2023 - got feedback from Fnb stating that they will terminate relationship because I allegedly traded with USDT. I know that trading with USDT is against the t’s and c’s of the bank. I told the bank that I am not trading with USDT and that they need to reconsider their position. 21/11/2023 - Requested feedback

up to today(23/11/2023) no feedback. absolutely ridiculous that this can take so long.