Breach of contract

I did a one year contract with them and they suddenly changed the name of the gym to BLAST and offered a $10 a month membership which completley crowded the place changing my level of service. It was hard to use the machine of my choice due to the number of members who flooded the place. I just never went back and thought I would allow my contract to epire and now they are calling me saying I owe them $60 for nothing!