What should I do about a contractor who screwed up?

I has a contractor fix a leaky window, and I knew he didnt fix it right, but he insisted that he did. He wanted to charge me $3550 for patching some holes in the exterior cenment and pathcing some drywall and I had a fit because I knew this wasnt the right fix and we about came to a fight. 6 months later the window is leaking again. Do I call this guy back? We ended up settling on half the price he charged which made him furious. What the heck should I do now?