MTN Upgraded my contract without my knowledge

I have a modem (my own for the last 3/4 years)..I use a MTN sim card on contract 2Gig for R99 month. I don't use it to make calls only for internet.<br> <br> MTN upgraded my contract on the 17/01/2016 without my consent. I send at least 3 emails to them and they tell me that I upgraded and I have a new handset..but I don't.<br> <br> If I need to upgrade I go into a store and read and understand the contract and then sign...I don't do anything over the phone or internet. They now want me to send an affidavit to that effect and the ***** unit will investigate. They are now inconveniencing me to fix up their mess and to make up for the problem in Nigeria