Telkom the worst service provider

I called telkom in Dec 2017 between the 21-22 to change my banking details and I was told they will be updated only to find that they weren't in Jan 2018. I called and had my details updated. In Feb I was billed R200.94 for payment rejection. My problem with this is I called telkom in time to inform them of my banking details change and the agent said that they did, I don't know what went wrong such that my details weren't updated and don't understand why I should be made to pay for Telkom's error. I have been calling since Feb to have this resolved and each time I'm promised that I will be called back by a supervisor and that a case has been logged and when I call the next time to find out what's going on I'm told no case was made and I am promised AGAIN that I will be called and a case has been logged. TELKOM I WANT MY MONEY BACK I'M NOT GOING TO PAY FOR YOUR MISTAKE.