Terrible service

I have been a client of FNB for almost 30 years. On 05/09/2022 I received an amount of R4700 in my savings account for two badminton rackets that I sold. On 20/09/2022, two weeks later, I received an email from Moipone Gumbi, FNB ***** Consultant, that FNB was notified that my account received proceeds of alleged ***** and that I must provide FNB with the reason for the receipt of these funds as well as acceptable proof of same, after which my money was frozen. It was not indicated at all exactly what type of proof I had to provide; I contacted the ***** department on 22/09/2022. The consultant informed me that I should provide proof of payment and an affidavit stating the reason for the transaction as evidence, which I did and send it to her on 26/09/2022. On 13/10/2022 I received another email from Moipone Gumbi indicating that I must provide proof that indicates that I sold the racket to this person and this after I had already sent the evidence, they said I must send. I have contacted M. Gumbi regarding the email and what is it that I need to provide. I have no other evidence as it was an oral transaction and according to her the proof of payment from the person and the affidavit I gave is not prove. According to her, an affidavit is not proof, and any person can get an affidavit, which is laughable, because an affidavit carries legal complications if it is not true. (An Affidavit is a written statement made under oath). It is absolutely pathetic that my money is being frozen, and I have to struggle to sort it out for something that is not my fault. I'm at the point where I'm going to close all my accounts and bonds with FNB, I can't believe I'm getting this kind of treatment after almost 30 years, I'm not a ********.