Contract ran its term, still being billed

I took out a Topup 100 - 24 months contract in Oct 2012, and the contract ended in November 2014. <br> <br> Now my name have a default, and my account has been handed over to their collection agency. I have <br> not made any payments on this account in 2015, because it expired. Yet the collection agency says I <br> made a payment to MTN on 06 Jan 2015 for R272.48. And now I have a bill for 6 months in 2015. I have <br> not received any service from MTN for this contract in 2015.<br> <br> MTN claims that I am still in contract and that the contract will only expire in December 2015. <br> <br> I would like to get this looked into and resolved, and not just a response. This is frustrating and a huge <br> inconvenience. <br> <br> I tried to get this resolved with the collection agency, but they arent able to explain or resolve this, so <br> I am appealing to MTN, to get this resolved. I have yet to receive any response from MTN regarding the<br> complaint I posted on their website. <br> <br> If I should not get this resolved with MTN, then I will have to escalate this to ICASA and any other organisations<br> to get this resolved.