Incorrect telkom bill handed over

On numerous occasions I filed a complaint with Telkom but after six months of battles they have as yet not resolved the matter. I had several cellphone contracts at Telkom. The accounts have never been in arrears. When one of the contracts reached the expiry dates, I contacted Telkom and opted to have it cancelled at the end of the service period. A third party then called me to make arrangements to renew the contract. After 3weeks the cellphone was not delivered and I contacted Telkom They could not find any records so I requested that they cancel the request as they were in breach of delivery contract. A month later I was billed for a cellphone that was never delivered. I reported this to Telkom and a consultant put a query through. She requested that the order be cancelled as the cellphone was not delivered. Telkom continued to bill me for several months in row for a cellphone which was never delivered. Since the month of August I have been in and out of Telkom service centres, made numerous telephone calls to their helpline without prevail. Now both Nudebt as well as Telkom sends stoporders to my bankaccount. I am also threatened with blacklisting by Nudebt.