Is $400 to resurface 50 sqft of peeled drywall a fair price?

I hired a drywall company to resurface drywall that had peeled down to the paper. I primed the paper before they started. I am unimpressed by the scratches and swirls that became evident after I primed and put on two coats of paint. I am questioning if I should ask the company to come back before I pay, or if this is just the effect of having dark paint. I want it to look better than I could DIY it, and I made it clear that I was paying to avoid amateur results. I had previously hired the same contractor two years ago to drywall an entire room, and he suggested skim coating would be more cost-effective for this project. I have sent him pictures and am waiting for his response. The paint was rolled only, except for cutting in at the ceiling. It's a satin sheen, and I was hoping it would hide imperfections. I didn’t negotiate a low price; I told the contractor to tell me what he needed to charge to make it worthwhile for him to make it not look amateur. I agreed to $400, having decided I would pay up to $500 for it to not look DIY.