I demand for my contract to be cancelled

I am so frastrated with mtn that i dont know what to do anymore. my contract with mtn ended October 2015 and i advised the agent i spoke to that i want to cancel the contract, however i want to keep the number and i was advised to migrate to prepaid. i agreed to that and the agent advised that she has put through a request to the retentions deparment for my contract to be cancelled. <br> <br> Now to my surprise, mtn has been debiting my account for the pasT two months and putting data and airtime in my phone which i did not request/ ask for. <br> <br> i called again, asking what going on because to date my contract as still not being cancelled.<br> i have run out of patience and need this matter resolved SOONEST!