SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

Just had a professional company install our system. The yard is relatively small so we have all sprays. It was installed last Wed and the first scheduled run was last Friday morning. Friday evening a pipe cracked and we had a large leak that ran for hours. Anyway, it took until today to get it completely repaired. Not a hampy camper with company. While he was out looking at that, I pointed out that about 10 heads were below ground level to the point that they were completely covered with clay. Our house is 2 years old and they trucked in a combo of red clay and sand for fill dirt. No topsoil. So,these heads are covered and he refused to install risers. He said that they are fine. Also, a few of the green backflow valves wound up being filled halway with the clay because the trenched areas drained directly into the holes as a result of a day of rain. He said that this is totally normal. DH and I said that sure some dirt will get into there, but is it okay to fill up with clay over the top of the on/off valve? It's been a nightmare with him saying he'd come out and he wouldn't show or he'd show up and forget parts. Oh well...hope it is all over now. My question is, is it normal to have heads sunk in dirt? Is it normal for the backflow valve junctions to fill half way with dirt and they will not be damaged? Also he installed the heads going down the driveway right next to the concrete so there is no way to edge -- do they make concrete or plastic donuts in semicircle shapes that can be pushed against a driveway? This process has been a huge PITA.