MTN worst service company ever

Tried to change a contract to a pay-as-you-go through a branch. They confirmed it was done. Received an invoice for normal billing. Tried to call to find out what is going on. The 083135 no does not accept the option to speak to any one. Held on for an hour on 3 occasions, and was cut off each time. When you speak to someone eventually, they can't help because it is on another system, they need to put you trough, then get cut off. No luck inn dealing with this company. Went to a branch again to help, they can't and don't have phones to call. A telephony company with no phones. Says it all about the company. They don't call back when cut off. Not sure where to from here. Hope social media may help. My vote is the worst company I have ever dealt with. DONT DEAL WHITH MTN SA