I had a cavity filling that fell out a few weeks after he fixed it. When I went back for another one, I let him know and he claimed that it's normal for that to happen. I had to pay once more to have him fill it.
I felt like he didn't know what he was doing at all. He drilled my cavities in so deep that one of them broke in half later on. I asked him why he had to drill it in SO deep - he does it for all of them. Overdrills, then overfills, then drills it some more, and leaves each tooth way too concave so food gets stuck in it every day.
Find a better doctor, even if your insurance is crappy like mine. That's what I did.