Unauthorised debit order

I have been begging Cell C for a settlement letter and till this day I have not received it. I have settled my account and therefore I do not understand how or why your have the audacity to debit my account. I am reversing this debit order and I would like my settlement letter. This is becoming ridiculous. On a monthly bases I have to be on hello Peter because of cell c. I am tired of your petty apologies.