debt

I signed up for blast about 3 years ago, when I did so I was told that it was a special only 24 a month and no contract. So I signed up was very disappointed the child care sucked and almost all the treadmills were out of service (this was my favorite machine) so I stopped going. Now all of a sudden they are saying I owe them 235 dollars or it is going on my credit score?! I told the lady I was told it was no contract she laughed and said no mam. Well who the hell was this employee that told me so?! Anyway want to see about disputing it I will be damned if I pay them money they definitely don't deserve but at the same time I am very worried about it ruining my credit.