Telkom *****!

I recently cancelled my mobile internet contract which was R907 pm. The last invoice I received indicated R0.00 due. My bank account was then debited for R160 without my knowledge and no indication what for or why. I reversed the debit order and received an sms with a case number. A week later I receive an MMS with an invoice for september for R459. Once again I have no idea what this is for because i no longer have any telkom accounts or sim cards but for some or other reason they are still trying to take my money. It makes no sense!