A creditor can garnish a checking account if they have a judgment. However, the judgement must be valid. In your case it may not be. However, until you get it "vacated" (i.e. withdrawn) by the court that issued it, it will remain in force. This means that the money in your checking account can be seized. Before doing so, a hold or "freeze" of about a month will be placed on it. It is during this time that you may argue the validity of the judgment. At this point, you will have to file a motion with the issuing court to have the judgment vacated due to improper service (i.e. you were not duly informed of the court proceedings, so you were not able to appear and fight the claim).