Upgrades undertaken without my consent

I have a contract with 6 lines with MTN. On the 14th February this year an upgrade was done on 1 line only. This was done telephonicaly via Rewards Co a marketing company for MTN. I am now informed that 3 of my of my other lines were also upgraded. No consent was given to these 3 upgrades. Since 2nd February I am trying to get assistance from MTN ***** division but no joy. Each time you call, you are transferred to Rewards co. Both MTN and Rewards co will promise to get back to you before the end of the day but nothing happens. I tried canceling or reversing the 3 unauthorized upgrades but was advised that this is now under investigation. This morning I contacted MTN again and was advised that according to Rewards co their investigation is now complete and the other 3 lines were legally upgraded. My response was that if anyone from MTN ***** department actually go through or heard the recording. Their reply was no, they are going by the info that was provided to them. This is poor service from MTN. You guys should have listened to the recordings yourselves. I called MTN customer service and asked them to reverse these 3 upgrades and was informed that a cancelation or reversal should be done within 10 working days. I explained to the consultant that I tried canceling earlier but was advised that this matter was under investigation. She hung up on me. How do win with MTN. I hope someone out there can assist. MTN - HANG YOUR HEADS IN SHAME