Cell C - Outdated Accounts

I paid up an account 3 years ago and today I decided to inquire about taking up another contract, I was told they cannot assist me nor view my account as it has now been handed over to legal. When speaking to legal I was advised that the account has not been closed due to the fact that the payment from SSDA (debt collectors) has not reflected (3 years later????); I sent the paid up statement AGAIN to the SAME Cell C email address and they still advised me that they're waiting on the payment to reflect. This is so frustrating and not the service I deserve after having ensured that the account is paid up and holding an account in good standing with you. Who do I speak to to clear this once and for all???