Telkom not billing according to the signed contrac

I signed a FTTH Telkom contract, the 1st 3 months will be R499 and the rest will be R999. Included I will receive a DSTV Explora. From the 1st account I received the billing was incorrect. After 3 accounts I have paid R438-45 more that the contract I signed for. Now I received the 4 account, which is supposed to be R999 pm, the billing amount is R1387-90. After numerous calls to the Telkom Call Centre, with no resolution, I again took the matter up with the manager Emile du Preez. His words, wait for the next account and see if that is correct. Well it's not correct. Mr Emile du Preez never return any of my calls and then I drive to his office, just to get the message the he is not in today. I have the following reference number ***1. When I phone with this reference number, they tell me the request have been rejected and then a new request is logged. I do not have the new ref nr. They said a dispute have been logged and they will get back to me. Nobody ever gets back to me, not even the manager Emile du Preez. I please need support to get Telkom to rectify my account as per signed contract