Did you sign the contract? If you don't sign it, it seems that you can get it back, but how can you get it? That's the problem, 100 yuan. Are you going to sue him at n times 100 yuan? If the owner is a good man, talk to him and he will pay you back. But since you say he has a bad attitude, there is no need to pester him any more. If you have time to pester him, you can earn this 100 yuan back.