Frustrated about paying to MTN

In Sept 2014 renewed/upgraded my MTN contract and took only the 1 gig data as my samsung tablet is still ok for what i need it, and for this the charge is R79. Ugraded my dayghters contract same time for R278. Which should make R357 pm. I have been billed and had to pay R557 every month since October 2014. I have called the customer services numerous times over the last 10 months and have waited on these calls for more than 30mins at my expense everytime, ref ***, ***, ***, ***. I have emailed and got a lot of automatic resonses and a few responses saying \my query has been escaleted higher"";not credit. If i had to cancel the debit order i would be in breach of contract......frustrated"""