I live in Edmonton, Alberta, Canada. Have an issue with a contractor…

I live in Edmonton, Alberta, Canada. Have an issue with a contractor building a patio-deck (314 sq ft). He seemed to know who to work with wood but not PVC plastic (Azek) deck. Here what happened.
1. He gave us a quote to make a copy of existing old deck deck (wood) with a PVC one - $8800.
a) he bought materials
b) I paid $4400
2. While removing old deck it turned out that a new retaining wall has to be built ($1150).
3. While working on it his price started to come up due to more than estimated amount of PVC boards (extra $750).
4. I quickly learned that while he can work on deck support, made of wood, his work with plastic boards were esthetically not good at all (messy corners, different spaces between joints, not leveled joints, etc. Anyway we met with him and explained him all that. Of course he promised to fix that. Well, he just could not as he did not have proper tools and skills to work with plastic boards.
5. While showing him few times those issues, his corrections were just not good, he did not take any pictures or drawings of the old deck and just did not do the copy of the old one, and whatever he did was not acceptable.
6. His base under the deck was OK but any plastic work was not at all. He also was messy, we had to clean after him as he planned to put garbage underneath the deck, as nobody would know – he said. We told him do not do it as this is a high end property, etc. He was coming to work late 10 am and leaving early before 5 pm (not sure exactly when). I would see him during lunch time. I had to fire him.
7. Contractor #2 - I hired another company that removed his plastic boards, adjusted wooden foundation, and finished this job. Final price for them $7,500. They reused majority of already purchased materials and a bit more $1500 due to damage.
Should I pay anymore to my first contractor (paid already $4400) ? Please advise.
JS