Invoice and Billing do not correspond

In December I received an invoice after transferring the contact into my name stating that my amount due would be R1082.98. On the 2nd of January 2015 they debited my account with that amount. On the 13th of January I received an invoice stating that the amount due on my account is now R28.75. On 30th of January they deducted R359.66. Not close to the amount due and they can't supply me with an invoice. I also had R1950.45 airtime on my contract before my upgrade that they now expired. No one informed me that I would lose the airtime. So I lost that money as well. Ont he 2nd of February I received a statement stating that the R1082.98 is now 30 days in arrears and the current amount is R28.75, so the next debit order will be R1111.73. <br> After speaking to Mbali she said that is not their problem. Neither the billing or the lost airtime.<br> I now want to cancel my account with them as they are *****ing my money.