Weeks? No, she should not go back to work at that job. She should either go in or call and and tell the dude that she will not work again for him unless paid immediately - on the spot - or she will march down to the county courthouse and sue for back pay. She could also go to the police station and issue a complaint for theft of services. He will then be arrested or at least served with a summons. She has every right to do this - at least in the US. I don't know where you are. Yahoo and the Internet is global.
In any event, were I her, I'd start looking for another job. This coffee shop is not long for this world.
Tell the owner she expects payment at the beginning of her next shift. If no payment is received, she won't be working that shift. Look for a different job, if an owner won't pay their employees, the business is in trouble.
First, stop going to work and only show up if they pay her what she is owed.
Second, find another job.
Unless your mom wants to continue volunteering, she should stop going to work and spend that time looking for a new job.
Every state has a wage and hour claim process. Google it for your state.
Let her get the money for a cup directly from the customer saying am not getting paid here.Sometimes this works.
Most likely call a lawyer and sue, if she's willing.
