I once watched a Jude Judy episode where someone took their car in for a repair. While in the custody of the repair shop, the car was broken into and things were stolen. They had it posted they were not responsible for any damages. The owner of the car took them to court to pay for the damages and losses. Judge Judy ruled in the car owner's favor. Reason? The repair shop had responsibility for safe keeping of the car and they were negligent in their responsibility to keep the car safe while in their possession. Even though they claimed they were not responsible, they were. They ended up having to pay for the loss and damage.
I don't know the circumstances or the conditions of your repair shop, but it is something to consider. Small claims do not take lawyers and the cost involved. Just because they post a sign does not mean mean they are exempt. Something to think about there?