Charging for services not received

Telkom convinced me that BizTalk 400 would be beneficial to me. I discovered it was not the case and notified them to cancel my contract. They acknowledged receipt of this but kept charging me for a further four months.<br> They said they would pass a credit which they duly did but their figures do not correlate with mine. I have therefore been paying my monthly invoice according to the monthly billing and not the incorrect brought-forward amount. More recently my line was out of order for six weeks and once again I was charged for the non-service. I worked out my corrected amounts, deducted the overcharge and made payments. My service has now been suspended! I was told by Afica that I must pay the full outstanding amount. Telkom will then investigate and pass me a credit.. I do not see why I should be penalised and have to pay for Telkoms negligence. Maybe I will be another ex customer.