Closure of account 6 months ago, still not done and service fees accumulate !!!

I sent a request to close my business account on 15th January 2021, I got a reply on the 20th of January to please settle the account as it was overdrawn. I immediately paid it up and sent proof of payment and requested closure immediately. 3 months later I get a call from attorneys to say that the account was handed over for bank fees for months after January. My account was settled and paid up on request, if fnb is not capable enough to do their job on time how does that become my problem. Also you can't speak to anyone in management or admin to discuss. This is the worst service ever from a bank who claim to be the best. Up till now they are still calling me for payment. So fnb please sort out your mess