Bally total fitness contract question?

My boyfriend and i just got a membership for bally total fitness and the girl said that we will not have a contract. She made us sign a waiver stating that they will take out $ from our bank account every 2 weeks to pay for our membership. The paper she printed out says contract on it,i don't understand what just happened. i have heard alot of bad things about bally but decided to give it a try please help