Bad service Cellc.

It's been over 2 weeks since i requested Cell C to remove my account from their system since I've closed the contract. And they have been reaping me off using my airtime instead of active data for my internet connection. I've been waiting for their legal team to send a paid up letter proving my cancellation and that I've paid them in full. As for the internet connection they are blaming me for things i don't have control of. Do i charge myself or deduct data from my account? Please assist further.