FNB not assisting

My husband cancelled our contract with Telkom Mobile 10th of July 2017. They still continued to proceed with deducting the monthly amount from my husbands account via debit order. He contacted them again and again and again, everytime to do the same thing - mail the cancellation form to ********** We mailed the original the 10th of July 2017, again on the 17th of November 2017 to Mpumelelo Hlatshwayo at ********** and then again on the 9th of December 2017 - still with no success!! Jadezweni Uhlume requested the cancellation form again which we sent the 12th of December 2017 again to ********** with no success. We were told they would escalate but this never happened!! My husband then decided to close his account. We are in the process of purchasing a property, which FNB don’t want to assist us because we “owe” Telkom money! How is this acceptable??