First, call the police. Generally, restaurants will refund your money through the shock of the police.
Second, find the local market supervision administration to handle it.
Third, if the above two methods fail, you can also tell the local people's court. The cost is not much, but it takes a long time and the process is troublesome. Of course, sometimes in order to protect your legitimate rights and interests, don't be afraid of trouble. After you won the case, all the legal fees were paid by the restaurant.
I hope the above answers can help you. If you want to know more about workplace rights protection, you can check out my other articles and synchronize them with hundreds.