You can cancel your credit card or maybe just replace existing card with different number.

The gym will not be able to charge you anymore.
Still you are subjected to the contract which always biased.

Thats is why I not going to gym because it always lock you 1-2 years.

They are unlikely to pursue you in court:

1. Not worth the money to going after you in court. Time and money.
2. You signed the contract without proper consultation and under pressure by the staff.
3. The contract usually very bias and 1 sided. They cant claim just as they like because of a contract. There are other laws which could overwrite the biased contract.

Most of the time - the gym will put you under CTOS.

Depending on your financial status, CTOS can be restrictive or useless.

Bad financial status - CTOS will stop you from getting loan.

Good financial status - CTOS does nothing and BANK still beg you to take their loan.
No bank will reject a business when you are a customer with assets and few hundred thousands in saving.