Letter confirming ********** contracts,, 7 months and still waiting

Last year my details were used to open two contracts with MTN, and i notified them and provided affidavits for cancellation. The contracts: A*** ,*** - *** were ultimately cancelled and they confirmed via email to me. However, these contracts are still appearing on credit bureau, I need a formal letter from MTN confirming the contracts were ********** opened and are cancelled, i have been requesting this letter for more than 7 months, no response, and this is affecting my credit score. Can someone attend to this urgently...