Was I wrong on how I went about this?

I recently made the mistake of hiring a friend to paint my house, I have a small ranch and when he came to my house he said ya $15an hour and that I would buy the paint because I get a military discount on it, I must mention he is not a professional painter, we are both professional full time firefighters who work opposite days so we do run into each other in the mornings. I knew he was doing odd jobs on the side so i figured he might want to make some extra cash on the side. When he came to my house for an estimate i had told him i don't need it to look like an art museum because in a year or two I will be adding a second floor on. I figured a day to prep the house as far as caulking and some little scraping in some stops that had to me done and 4 days 1 day for each side of the house and maybe a day or two more at most so I was looking to pay him $600 cash for 40hrs and then pay him if he went over that. The first day he showed up at 10-1030am with another guy who was 65-70 years old, they caulked the house and started painting, when I got home from running an errand he had mentioned it would be a good idea to put some crushed stone down at the base of the foundation to stop the moisture from coming up from the mulch to the shingles. I had told him it was a good idea but I can do that later on myself. Day two they show up again 10-1030 paint for a little bit then take lunch, I had called him while i was at the firehouse to see the progress and he said there is a lot of prep work that had to be done but they were on there way home from home depot because they ran out of paint, I was pissed off the bat because if there was so much prep work to be done why wouldn't you continue to prep until I can get the paint in the morning so I can get the discount. My father in-law was home watching my daughter so I had asked him to take a picture and send it to me over the phone, when i got the picture I noticed something at the base of the foundation, zoomed in on the picture and it was crushed stone that he had put down, I called and said "who told you to put the crushed stone down?" and he said no one i just wanted to give you a visual. I told him i am paying you hourly to paint the house not do landscape work, just paint the house. I couldnt believe how little they got done in 2 days, but I guess when you work from 1030 to 330 4 and and take lunch your not gona get much done. I was getting concerned about how much this was going to cost so I had asked him to speed it up a bit and that my wife and I would like a flat rate instead of paying by the hour, so he went home and sent me an invoice which had a fuel charge on it sales tax, and labor for the other guy he had with him and fuel charge (he lives in the state next to ours) which none of these things were agreed to in the beginning also on the bottom of the invoice was a note that said because I was not willing to pay hourly that the $15an hour was void. He sent me email after email stating that he will not accept phone calls from me and that all conversations will be done over email. I got so sick of the emails and 6 invoices that I had told him that I am leaving an envelope in your locker with cash in it for the hours "you" worked which we agreed upon end of story. When I returned to the firehouse for my shift he had left an envelope in my locker with a note attached to it that states "obviously you need this more than I do" and the cash was in there that i had given him. He states that he refuses to put his professional stamp on a house that's just "slap the paint on there" but he has no company name isn't licensed and i was invoice 101 and if you don't know invoices start at 100. If I wanted to pay big money to paint my house I would have hired real painters and they would've been done in 2 days. I just want to know if I was wrong in anyway in how i paid him, I really believe I did the right thing.