Unscreened Compost from Landscaper Upstate NY

I recently hired a landscaper to do my 4k square foot backyard. He suggested compost, fertilizer, seed and straw. I took him at his word that this would be the best route.

The job was completed and I allowed the grass to come in for about 3 weeks. When I started investigating the lawn, I found rocks up to the size of my hand scattered throughout the grass which clearly hindered its growth in spots. I ended up filling a quarter of a 30 gallon lawn waste barrel with rocks at least the size of ping pong balls (picture attached).

I raised this concern with him and was told that is simply how unscreened compost is. He showed me a sample before doing the job that had clumps of organic material, but definitely no rocks. If I had known this would be left behind then I would have never agreed to it.

Did I simply get hosed by a bad landscaper?