We rented a musical instrument (Cello, for the Middle School student
in our home) that was damaged while in our possession. We want to pay
and close the matter. The shop owner wants to charge a lot more  (>2x)
than the estimate from our expert. What are our choices and options?
The shopkeeper wants to take the instrument from us and submit it for
more estimates. Should we take some photo's before handing it over? My
spouse recalls signing an agreement and we don't have a copy. We used
a credit card to make periodic payments and finally, if it matters,
the music shops in this area (Peninsula/South Bay, CA) seem tobe a
very connected community. We don't mind paying what is fair and just
don't want to be taken advantage of.

I have spent time at the library and looked thru the Nolo books; Also
went thru the Attorney General's web-site for somncumers; Neither were
all that helpful;

All suggestions are welcome.

If you have a reputable repair service who has provided you with a
reasonable estimate, then why don't you just have the instrument
repaired by them?  If you return the repaired instrument back in its
previous condition, then the shop owner would have no claim against
you and there would be no debate as to cost.