STILL BEING BILLED 4 MONTHS AFTER CANCELLATION!?

Sent a cancellation agreement in to Telkom on the 22nd of June with reference number ********** 32A. We have still received bills every month since, and have phoned NUMEROUS times to sort this out. Every person has assured me that the problem was sorted out yet WE ARE STILL BEING BILLED FOR A SERVICE WE ARE NOT USING???

According to Telkom, they owe us a credit of R260 and thereafter the cancellation will be processed - WHY HAS THIS NOT HAPPENED and why the hell is this STILL not sorted out???