Homeowner not paying

We own a small home improvement company in Atlanta GA. We entered into a contract with a homeowner for remodeling. We completed the work, homeowner says he's satisfied. We have a contract that specifies payment upon completion. Two weeks after completion, he still owes us $1500. Do we go to small claims, file a lien or what?

File a lien. It is usually the easiest to do. If you have a problem with the lien process, file in Small Claims.