Vodacom refusing with clearance letter after disputing ********** account

A ********** account was opened under my name with vodacom. I disputed this account, and upon investigation I was informed by a consultant from vodacom that the account has been closed and credited. Now I need something in writing because if I apply for a bank home loan I am told that my vodacom account is in arrears. Vodacoms collection department has been promising to send the clearance letter but no sending. I have called countless times.