Lies and Nightmare

I cancelled the contract with them in less than a year after joining and i have never used their service after deducting the R300 every month while i have paid 1950 as an initial joining fee. 3 years later im receiving threatening emails and calls that i have to pay 747.50 for cancellation fee or else they will send my details to credit bureau so that i can be black listed. Whereas at the moment of cancellation they never told me about the cancellation fee. They even have guts to tell me about Consumer protection act. Yesterday i received a call and email from a guy by the name of Fezile Mokoena who even send a picture referring it as a copy of my contract, which doesnt even have my signature nor my details. The picture only have the summarised money calculations. They even gave me 14 days to pay the cancellation for the contract i cancelled 3 years back where by they even requested a formal email for cancellation request back then.