If you dispute the wage garnishment, you will need to fill out and send the IRS Form 12153, Request for A Collection Due Process Hearing.
This must be done within 30 days after receiving notice of a tax levy being served against your wages. Your appeal will be filed with the IRS Office of Appeals. Here is a sampling of some of the issues you may discuss at the Collection Due Process Hearing:
An IRS garnishment is another term for levy. You have the same taxpayer rights as if dealing with other tax levies. Anytime, in fact, that you deal with the IRS regarding any tax matter, you are protected by the Taxpayer Bill of Rights.