When you apply for a fitness card, you will sign an agreement, but usually the customer will not read it carefully, just sign it, pay the money, take the card and leave. In principle, there should be detailed regulations on it, explaining what kind of situation can be returned and what kind of situation can only be asked for leave. They are made by staff. Can't I return my card? Or did the staff tell you when you handled it, is there any discount on this card, and you can't return it if there is a discount? So, according to the contract, you will be punished if you don't pay the balance.