********** Sale - Sell Direct in Breach of Sale Agreement

I received a call from Sell Direct offering me a smart internet 5gb deal + router for R139pm in early August - it was explained to me that my bill would be pro-rated to the next month and I was fine with that. So basically, if I didn’t use any extra data my bill was supposed to be R278 - Ok sharp. Then the Invoice comes in early September.... From the looks of things, I am going to charged R240 pm for this contract. My bill now includes a device subscription fee of R40 (which I had explicitly asked and confirmed that I would not pay) and also, my Invoice reflects that I am going to pay R199pm for the 5gb (not R139pm as sold to me). My bill is now +R450 for the 2 months and no one can explain to me how? When I call Telkom they say they can’t help me because I purchased the device from Sell Direct - and when I call Sell Direct, the phone is NEVER EVER answered. I am very upset...