Horrible service from African Bank

I have received horrible service from African Bank! I mistakenly deposited R3000 into a credit account that I paid up and closed almost 2 years ago. I requested a refund on the 19th of January and provided proof of payment as well as my banking details. I was then told the refund would be processed and paid in 72 hours. Ten days later I had not been contacted or refunded so I called to make a follow up only to be told that I need to submit proof of payment which I immediately sent to the email address provided. I kept calling to follow up, only to be told that the proof of payment was not received. Six emails later I was told that the request was declined because the account was in arrears. I emailed the paid up letter that I had received from them and ever since that I keep getting different stories every time I make a follow-up...from being told the payment has been processed and will get the money anytime which does not happen or the request was declined with no reasons. I just don't know what to do anymore. African bank, your service is horrible to say the least! I need my money or tell me if you do not want to pay me and I will take this matter further.