Fly wheel repair?

I am the original owner of 1995 AUdi A5 ((base). Before stalling, the car was making a very slight clicking sound. When accelerating the engine slowly stopped a few seconds later. I tried to start the engine and it would slowly turn but not actually start, so I thought it was the starter motor. The first mechanic (independent VW/Audi) said it was definately the starter because it was not engaging. When I asked to see the part being replaced, the mechanic said take your business elsewhere and charged me $65 for the visit but never disclosed there was a charge if no work was performed? I took the car to another mechanic that only works starters and alternators. The second mechanic said, he tested the starter motor and it was working (previously starter was rebuilt and installed again). But the second mechanic also said, out of curiosity, he touched the fly wheel and it turned, that it is not suppose to turn, so he recommended another merchanic, $550 labor plus parts. Can a rebuilt starter motor be faulty to the point an engine does not start? In other words, can you tell if a fly wheel goes bad or bolts come loose, or can it be as simple as a starter switch and motor that was rebuilt one too many times?