We got Blacklist due to Disgusting Service

We placed notice to cancel our service with Telkom on the 30th June 2016. Our documents were received and confirmation that the account would be closed was given to us. Since last year deductions for the premium was still being debited from our account and our endless attempts at resolving this issue was ignored. We went into telkom stores and called the service centre who all made empty promises. Eventually we were then told we are owing an amount that will accrue interest which was unbelievable to us. Telkom then went on to Blacklist us for this amount which we eventually paid just to get them off our backs. We are now applying for a home loan and due to the pathetic service and ignorance from Telkom it has now reflected negatively against our name and the banks are requesting a letter from Telkom which we will probably never recieve. Thanks for ruining our credit score!!!!