Can a restuarant/bar/club legally take all of the service charge and not give any of it to any of it's employees?

California labor laws prohibit an employer from "collecting, taking or receiving" any tips or gratuity left by a customer for an employee. A tip/gratuity is a voluntary amount left by a customer for an employee. However, a mandatory service charge is not the same as a tip/gratuity. A mandatory service charge is a fee that an establishment imposes on its customers (i.e. a shipping company imposing a "fuel surcharge" on top of its package delivery fees). Because mandatory service charges are not amounts voluntarily left by a customer for an employee, an employer is free to do whatever they wish with the amount collected as mandatory service charges.

You do not mention what this service charge is actually called (is it called "Service Charge" or some other name), and how this service charge is communicated to customers. If your employer is misrepresenting to customers that the amount is really a tip/gratuity that will be paid to the employees, then it would appear that both your employer and the customer understood the fee to be a tip/gratuity. In such a scenario, your employer would be estopped from denying that it was not a tip/gratuity.