Customer service nightmare

I requested a speed upgrade on my Telkom fiber line in January. Telkom sales department was very helpful and assisted me with my request until I received my bill for February - I have been charged for 500Mbps line but I requested 50Mbps line. After numerous phone call to Telkom Sales department, Telkom technical department and Telkom sales department on the 11 February I was assure this issues has been resolved. Telkom technical department informed me that my line speed was just 50Mbps. When I received my March statement again I have been billed for 500Mbps. I phoned this morning and the sales agent advise me she will phone me back - Never did. I phoned Telkom sale again this afternoon to get this sorted. Just to be on the phone for 20 min with Telkom Sales & Technical department so Telkom Sales can just confirm what I told them that my line speed in not 500Mbps and also not what I received. I have received worst customer service today. I have to phone Telkom the whole time and waste my airtime. This was Telkom error and the agent confirmed this. Worst part is that I have been Telkom customer for more then 5 years but after today I will be moving to another service provider as I can't be phoning Telkom every month to sort out their mistake