Unauthorised debit orders

It’s very frustrating to have money debited from your account when you not owing. I have a credit card which I settled and was told I will get a paid up letter after 3days to date I’m still waiting. But now African bank debit from my account while I’m not owing. We I’m requesting a refund the consultant hung up my call. I’ve been calling them but with no assistance they will just mute the call. Now I’m being told my account is arrears what arrears because I’m not owing. Why is their system not updating automatically. I requested a statement it shows zero but I get calls that I’m in arrears how. I need my money refunded