Unhelpful but to be expected

I have a fibre account with Telkom and selected a debit order payment method. I had no idea that Telkom places a Debit order cap on their debit orders because it is not something they explain. What the cap does is it only debits your account for the value of the contract but if you use the phone or go over the cap amount, they do not deduct that and it goes into arrears. This happened to me and on my side I guess I should have been more mindful but I thought they would take the value every month. Nevertheless, I settled the arrear build up which was about R120 or so and now they have listed me on ITC. I have been trying for 6 days for them to take it off but no help. Everyday I am on email with them but its like writing an email to a ghost department, no one replies. Not a word. I am trying to applying for a bond and need a letter that states I owe Telkom nothing but for 6 days still not a word, I might lose the house because of Telkom's uselessness.