Telkom worst service ever. Suspended my account when the last invoice shows a credit balance.

Telkom sent me an invoice on 12 Aug showing I have a credit amount of R503. On the 25th of Aug I still made my monthly payment but yet they suspended my account. How can my account be in arrears when you just sent me an invoice showing a credit balance. I called them yesterday and the lady was not helpful at all as even now my wifi is still not working. Telkom must be the worst, their systems seem to not be communicating to each other. I don't know how many times I've had these cases with them, it's tiring.