Bad service and *********

I had a cheque account with standard bank and stopped using it in 2019 after having debit orders returned unpaid and went to Bela Bela branch for assistance but they failed to assist me and there was money in my account, so after few days I went to close the account and they refused saying I owe them bank charges and they even took my 250 which I saved frm the linked account. Today they say I owe them almost 7000 of bank charges again