Never accept a cellc contract

Cell c called me 3 years ago and sold me 2 year contract for a pocket router, i paid everymonth via debit order and never missed payment.before the last month a received an sms for renewal option i called to advise i will not be renewing the contract and therefore the router stopped working after the last month.i now received notification from the credit bureau that cellc has listed me as a bad payer. I do not recon for anyone to accept any contracts from cellc never but a money making scheme company