I don't think so.  Your employer, or your employer's client, has docked your pay for not doing your job properly.  If there are more facts to this situation, beyond what you've included here, you should discuss the entire scenario with an attorney in your area, or the New Jersey Division of Wage and Hour Compliance.Unless you had a written contract, however, you were employed "at will," which means that you can be fired for no reason at all.  So, a less drastic job action, docking your pay, is also usually not something the law will correct.