Job NOT done

I booked my Samsung Galaxy S4 in to the MTN store in Cavendish square as it was giving too many problems. At the same time, I cancelled my contract before matured and rolled on from month to month. Forms were signed with Kelly, her contact number is ***. A month later MTN deduct over R900 from my account, please keep in mind that I used to only get billed R450 per month for my contract, so to be deducted double for a contract that I cancelled is insane. My wife is now getting constant sms messages to her number stating her number will be suspended and she's been on contract for a two months now<br> <br> I need answers because I cant get through to customer care as the line cuts out, I've been calling them since getting these messages. In the past I've called and had no luck as MTN was on strike. If this goes on too long i'll probably get blacklisted and MTN will say it's my fault. I need this matter resolved urgently and dont know what else to do