When I was working in a hotel, I found a guest's mobile phone and hid it. Later, the guests came to me, but I refused to admit it. Finally, I went to the police station.

These are two different things. What you found is not your fault, and there is no legal punishment, but you have affected the reputation of the hotel, and you can't be fired. The hotel will not compensate you for the termination of the labor contract, but you still have to pay, which has nothing to do with your fault. If you refuse to pay, you can complain to the local labor arbitration department.

That's what you said. If you don't find your mobile phone the first time but violate the law, there will be corresponding public security penalties, but the hotel has no right to punish you.