MTN- Unlimited Wi-Fi Month to month Contract

got a month to month unlimited wi-fi contract, after receiving the router, it lasted a week and i received a message to say i run of data. i then called to canceled the order as it only lasted a week instead of a month. i was told to cancel through call center, and they told me to return the router at an MTN store, i returned the router on the 11 June, called the call center to cancel, was told i can cancel only at the store, went back to the store, the consultent at MTN fourways was very rude, and they refused to cancel the contract, was toldi can cancel through their customer care, i called customer care while at the store, and it was a debate between them and the store to who is supposed to cancel the contract. i was given another number to call, they told me their system is offline i should call them the following monday. Monday i called, and they told me the contract was cancelled, and it will reflect after 21 days. Mtn still send invoices every month trying to debit even though i don't have a sim card or router, i called them countless time without any success. wish someone warned before i took that contract. Poor service to the core, both at stores and through call center.