If you want to get it off your chest, you can file a complaint with the Better Business Bureau. You can also complain to your state and federal representatives, in the hopes that the company will be legislatively punished. A third option is through your state Attorney General consumer protection office, since they typically have sympathetic staff who will listen and if the problem is severe and repeated in your state, the AG might take legal action (w.r.t. the company). Since this ultimately involves the Department of the Treasury, you can complain to the Dept. of Treasury.
The other end of the complaint spectrum is to file a lawsuit or some other legal action seeking relief from their wrongs, that is, you could sue the company (hire a lawyer who files a lawsuit). The problem is that unless the company broke a law, the matter has been resolved and you were not legally "harmed", and the courts can't just punish the company for annoying you. There are laws against debt collectors harassing people and associated punishments for violating those laws, but no law prohibits making an honest mistake. For there to be AWG, there first had to be notice given. This allows for a hearing concerning the very existence of the debt. So it is unclear how you got to the point of Treasury issuing an order to the employer. If the mistake was made by Treasury, you can't sue the debt company.
