Debating my account for a contract that does not e

In 2012 I took out a data contract with cells. This was a two year contract which expired in May 2014. It was R99 per month for 2 gigs. It then switched over to prepaid and I used it until November 2014 as it was costing around R800 per month. I now see that I am being debited R279 per month. This is *****!!!! You do not even have a contract or prepaid contract at R279. I want my money back otherwise I am taking you to Court for theft and *****.