Credit bureau

IWSpproached by a sales person from the gym company to join the gym while i was working at Maponya Mall, i filled inn the forms but within 7 days i went back to the consultant and told him that i dont want the gym anymore and which he told because its stl within 7 days and the application has not been processed he wont submit it through. I was suprised after more than 5 yrs of cancelling my membership where no one has ever called me to say i owe the gym or any letter for that matter i've never received, and now sometime in March 2015 ive been receiving sms for some amnesty to rejoin the gym and when i check my credit bureau i found out that i have a default of abt R7000 from the gym company which i never ever even set my foot on their door step. No one has ever called me to say i owe the gym ive been using the same number and the same address for more than 10yrs and no correspodence this company and now that ive managed to clean my credit status they just pop up frm nowhere...i want that default to be removed