You ABSOLUTELY do have an option...
First you order the mechanic to button up the plane and sign off on
his performed work in the logbook and his list of discrepancies, and
you pay the bill...

**Remember, the Annual Inspection is only that - an inspection... It
is not graven in stone that the first mechanic is the only one who can
correct the discrepancies...**

Then you move your plane out of his shop and secure it...
Then you call the FSDO for your area and ask for a ferry permit for
this plane because of a dispute with the A&I... You read him/her the
list of discrepancies, such as the small dent in the exhaust that has
been there for a decade, etc. and ask for the ferry permit to move the
plane to another shop for a fresh inspection...
The odds are 99 & 44/100% that you will get the ferry permit...
The odds are also good that the FSDO inspector will stop at the new
mechanics shop to have a look so be sure your VOR checks are logged
and your ARROW is straight and shiny... Once the new mechanic and the
inspector agree on what is an actual discrepancy you get the work
done, and your plane is now airworthy again..

denny