burning oil

A while back the head gasket went in my tercel (?93): I had it fixed along with getting the valves redone, i week later the car over heated. I found that the garage didn?t tighten one of the clamps on the hose from the rad to the engine. I took it back and they said it didn?t hurt anything, but it started to burn oil badly. I took it back again & said that the over heating must have done damage which caused it to start burnig oil. They told me that the rings were likey bad, but it wasn?t from their negligence, I think it is b ut can?t prove it. What do you people think?? Is there any simple solutions besides a ring job?? Thanks in advance; dunc