If an electrician over charges me and I already paid him, Do I have recourse?

the city said the lights I have in my store have to be changed.they are not allowed. the size is a small bodega.the inspector said I had 1 week to correct theproblem or he would close my store for 30 days. It is very hard to get an electrican in that time frame, so i got the first one who aid he would do it. he charged me $6,000.00 and I gave him half anf the other half when he completes the job. Everyone tells me I got ripped off big time. he is a license electrian and the only one I could get.. can I report him for over charging me??