Dishonest Roofer./ Dishonest Contractor advice please.?

I just recently had my roof done. had my ins adjuster come out and look at it (storm damage) and was approved for a new roof job. OK, I am new at this, have never had a roof done before, so I guess I just didn't know the 'right " questions to ask.

the guy was recommended by my next door neighbor who had his roof done by him. Ok. this guy seem to be professional, polite, and to the point... no dilly dalling! so I gave him the paperwork from my ins company (saying the $$ they would allow me for a new roof) and he was happy, and with-in 3 days they were here doing my roof! I did ask him prior how much my roof would cost? he told me for 4 to 5 thousand bucks... I do not know about these things, and said hmm, ok. (my house is small- 2 bed room, sits on a 50 foot lot.. (teeny house) to try and make this a little shorter-- the guy done my roof (it does look nice) took the first check the INS COMP sent to me (just over 4 thousand bucks) I asked for a receipt he told me he would get it to me, by this time I had already ask for some type of invoice, or paper work-- he would not give me anything!!! finally my INS lady called me to ask me about the roof job, he had sent her 4 different invoices asking for MORE and MORE $$$ saying he did lots of things to my roof he did not do! AND to top it off, AFTER he was done with my roof, he had 10 packs of shingles left ver in my driveway--- he wanted to roof my detached garage for another 250 bucks out of my pocket- I declined him, so he took the shingles with him (I have the delivery invoice) of what all he ordered for my roof job (he does not know I have it) and am I not supposed to keep the left overs since my $$$ is paying for it???

please any advice is greatly appreciated.

thanks