FNB the worst client service

FNB Upington is the worst bank you can bank with. I was I client and in 2021 I closed my account. They send me a message I owe them money after I closed my account with them. Went to the bank and tried to close the account and they said I need to pay. I paid the money and after two weeks they said they will refund my money. I got a call from FNB afet 2 days and the said they will not refund the money I can come in and close the account. I went to FNB to close the account hand to wait 30 Min and wasn't help. I left the bank now I want to know how do you close a account and after 5 years you here you owe money to the bank. After 5 yeas and I'm still trying to close the account. This is bad service from FNB Upington.