Cellc Cellphone Contract

I had a cellphone contract with Cellc. Contract expired 2018 around Sep, i wrote contract termination letter, contract was never renewed.

I called numerous time to request confirmation letter, never received to date. On Clear score still shows as active and in RED, as if am still owing them R143, its almost two years now, but records are not updated and this is affecting my credit scoring.

I need help please.