********** contract and no customer service

I was signed up for a data contract with MTN over the phone. I was promised a data contract for R149.99 a month over a 2 year period. I remember because I specifically asked and was told its a 3 year contract after which I said it is either 2 years or no deal. I was told it was fine and I would receive my sim card and contract by email so I can review all the detail. My sim card was delivered by I received NO further correspondence or any contract from MTN. I did not even have the NUMBER of the card, so I couldn't even activate it. This was beginning of May. I phoned MTN call centre, but no one picked up. I emailed them and received an undelivered reply. Then I received my first INVOICE on 18 May for 1 June. I reviewed my bill and saw that I was being billed R228.43, not the agreed R149.99. I tried to phone 083135, again no luck. I emailed them to request an urgent call back. After about 2/3 weeks someone eventually phoned me and I explained the whole story. I was told that the contract was in fact 3 years, not 2 as I was promised. I asked for the contract to be cancelled immediately and to be refunded. I was told this will be escalated, they would listen to the sales call and then cancel the contract accordingly. Since then, I have been billed AGAIN for July. I have sent multiple emails, I have contacted them on Facebook, I have phone 083135 repeatedly. I keep on being told it has been escalated. One email even stated it shows my query has been resolved. Resolved??? How?? I am being billed for a service I do not use and was sold **********ly. I have tried to phone my bank to stop the debit order but this can only be done by MTN. So now I am a sitting duck. Two months and MANY follow ups later and still NOTHING. I have never in my life received such bad service and I cannot understand what is taking so long??