HORRIBLE SERVICE AND LACK OF COMMUNICATION FROM TELECOMMUNICATION COMPANY

What does it take from cell c to provide a detailed statement to indicate the alleged amount I owe them. The account was on debit order and paid to term. They failed to respond and now this is affecting my credit score, I don't know how will the query be resolved if they cant provided information I need. I have existing contracts and I cant wait for them to end and cancel all of them. I will never recommend anyone to this company due to horrible service.