be ware of gym company

last year around end of april i met with one the gym company sales person at south gate mall he approached me to sell the gym membership which i told him i was not interested as i did not have time to gym due to me schedule , the sales person by the name sabelo then offered me a free trial for a month which he said i could go to any of their gym and then after maybe i would change my mid and adviced me that i should fill in some form in order to get the free trial entrance document little did i know i was signing a gym contract. this year in october i recived numerous sms that my gym account is in areas and when i call their number for the bara gym the number is always busy ,when i do get through they tell me they will call back which they never did.now i have received a leter stating that i owe them R8,209.00 *** with a threat to black list me if i do not pay. i just dont understand how i owe this money because according to me i dont have a gym contract and im not intending to have one in the future<br> this is *****.no one has contacted me about the debit orders i have never activated the membership and how on earth do i owe such monies for a gym contract this is insane