Doesn't seem fair to me. You may want to check out dol.gov.

One question: are you exempt or hourly? If you are exempt. . you should have a base pay that cannot be 'docked' for customer complaints. A lot of questions here to get to the bottom but one thing is for sure. . every state has to follow federal guidlines unless the state regulation is a better benefit to the employee.

Hope I was somewhat helpful. . . but I think it looks and walks like a duck.