unathorize deduction

Hi<br> I don't understand my contract expired on 05/02/2015. But I was told that the contract they will be able to cancel it at the end of February 2015. But in January 2015 I was billed R326.99. that covers the end of February 2014. I was given 2g. I only used that 2g and nothing more. And at first my contract was R118 for that 2g. there was a month that I overlap that I was billed at +-R350. And I complained and I was told that I used more then I arranged that my data be stopped when my 2g is finished. They said that they can only make it over by R50. Then if is my 2g for R118+50 =168. That will explain the 326.99 for January and February if I double the amount. At the end of February 2015 the simcard was disconnected. <br> <br> My big question is why then have you billed R299 at the end of 13 march 2015. Please explained? <br>