Gym Company Ruines my future

Around Feb 2014,I was approached by a Gym Company salesman in Maponya Mall.The guy requested me to join the gym,I app**** but with immediate effect asked the guy to terminate my app as I don't have a gym around my residence and that will result to unnecessary expenditure for traveling just for gym.The guy agreed to my reason,Now a year later.In 23 March 2015 received a FINAL BLACKLISTING(for R8664) letter from the Gym Company,You can imagine my shock as to my knowledge the app has been terminated,Well I guess it wasn't,What shocked me is that when I app**** I gave my contact details,Which Gym Company didn't put to use.They never called nor emailed me to inform me that I missed payments...I have given them my banking details they didn't even debit my account.When I went to their offices in Maponya Mall,the lady who assisted me didn't care about my situation...She told me that I MUST PAY UP OR ELSE ILL REGRET!!!...Today I am unemployed and can't find employment due to being blacklisted for something I have never even used.What makes it worse is when talking about my experience with my colleague I am actually not the first I have more than people under my belt.