ARREARS ON MY CREDIT SCORE BUT DONT HAVE A CONTRACT WITH CELL C

i emailed over a week ago and called querying why cell C arrears is reflecting on my credit score when i haven't had a contract with you in years??!!!

No response to email, call the call center and an *********** agent answers and requests the same infor 4 times??!!! ID number, resident address, full name!!! CASE: ***