GYM CO (PTY) LTD Listed me as a Defaulter

I once signed for gym with the above mentioned Company but have never been to their gyms not even once but today when I check my credit report there is R8339.00 loaded under my report which they say I owe them for what because I never used their facilities not even once, I want people to be aware of such Companies which rip people off and to my surprise how can they continue charging you for the services they haven't rendered, if you people at Gym Co (PTY) LTD can read this, I demand this removed under my name because this wouldn't be the last message I right on this and will refer this to my lawyers.