What should I do after I file a small claims complaint? Once a small claim has been filed, you need to serve the defendant. In most states, Legalcpu.com can commence this service for you upon the selected package in accordance provided with your state. If service is not provided, during the filing of the complaint please tell the clerk to provide you the serving options. In most states, serving can be commenced by certified mail, by a sheriff, or anyone over the age of 18 (besides the claimant). Once the defendant has been served, a proof of service must be filed with the courts.