what can i do if father is not paying full amount of child support?

Short version: file a motion for contempt, etc.  Bigger picture: you will not get far "feeling" that "he might have another job."  courts are concerned with evidence.  There are a lot of ways of getting such evidence -- yourself or through agents, ranging from knowing someone seeing him going to another job, to hiring a private investigator to getting and reviewing his tax returns (if a W-2 job, there will be a paper trail).  Of course, everything but the do-it-yourself options will take money to accomplish.  In the meantime, of course, every month's arrears are accumulating both interest and penalties.  See: http://willicklawgroup.com/child-support/ http://willicklawgroup.com/interest-penalties/ Ultimately, this is a cost/benefit question for you.  You can wait, or file a motion on your own, or perform an investigation on your own, or consult with and hire a lawyer.  There are no guarantees as to how any of those options will play out.