MTN Upgraded my account without my consent or approval.

I have a data simcard in my router and was on the MTN Uncapped Lite package since 2012. After the 24 month contract I went month to month. Now when I've checked my email MTN has upgraded me to the My MTNChoice 30GB package without my consent or approval. I cant afford this package in the first place!!! NO phone calls to ask me if I want to upgrade (because simcard is in the router) and NO emails asking me if I want to upgrade. Only an email saying "Thank you for upgrading with us". Went to the MTN shop in the mall to help me cancel, all they saying is its on the old system I must call 135. I called 135 and after 1 hour 37 min 59 sec on the line NOBODY and I'll repeat NOBODY could help me cancel this contract. I WANT THIS CONTRACT CANCELLED!!! I DID NOT APP**** FOT IT!!! NOWHERE!!! My Account number A*** Data Simcard cell number ***