Good Luck Trying to Cancel MTN Contract!!

I took out month to month data contract only to find there is no coverage in my area after specifically asking the agent to check and I supp**** my address). I have been trying to cancel the contract since August. I was told to return the router to MTN store near me, both refused to take it based on that they are "Agency stores". I drove over 100km's to Durban to return and went to Musgrave, Pavallion and Davenport stores, all refused to take the router stating that I took it out with Rewardsco call centre. I've logged collection request with DSV courier who states they need MTN approval to collect, MTN says I must cancel with Rewardsco. Rewardsco says they are not permitted to cancel month to month contract as per instruction from MTN. I do not know what else to do as I'm being billed for a router I cannot use and its address locked as well apparently!! Absolutely horrible experience that has cost me more than its worth! NGAZE NGAZISOLA!!!