Cellc sucks

Cellc. Shame. They clutching at straws. Instead of nurturing and servicing existing clients the entity acts with impunity. I have a near perfect credit score of 85... All my other accounts are up to date, home loan, credit cards, municipal account etc.. the only one thing causing *** is good old cellc. Sigh! I instructed the entity cancel and discontinue my lapsed 24 month contract... Which wasn't done. Now I'm being bul**** by cellc collections and apparently owe R800 for a contract I don't want or use... Apparently my request and my rights have been totally disregarded. When I visit the store I get the 'dead-fish-eyes' response... What to do? Who to ask for help? Or am I doomed?