Without knowing what you said, we have no idea if he can successfully sue you. But, he doesn't have to pay a lawyer. You would.

Yes it is. They don't have to consent to being recorded.

No, but you can report them to the state.

Google underage teen scam. It is probably a scam. Ignore it.

You continue to ask the same question, and continue to get the same answers.

There is nothing to sue for. Find another gym...............

You do the same thing you would do with any other product you buy that is defective. You return it for a refund.

This is a Q&A forum. You have not asked a question.

Sounds like good police work. Lawyer up.

The only thing you can sue them for is to require them to produce the certificate, not everything that happened afterwards.