@ripped off, You failed to mention the year, make of car, how many city, highway miles & if the car has a clear history of regular interval checkups. You did state Freon but did you say Freon loosly or the newer refridgerant. In today's world A/C is a big issue with the theory of depleted ozone. The Gov believes it so if you (as a mechanic) have better follow standard protocal. Keep in mind these systems are very sinsitive. I assume you did not buy the car new because if you did, you should have a report with your dealer's service dept. They should know your name when you come in. Meineke, as well as any mechanic, is not allowed to emit any cfc's and the act of doing so can be very costly. That is why there are so many fees associated to simple auto tasks today. If your A/C system had been low or dry for some time or if someone had attempted to prime an older system with the newer refridgerant this could/would damage your system. which is subjected to all kinds of elements . Those rings dry out & shrink, those fittings become corrosive & tight. The tubular ends tend to twist when attempting to break free the fittings, etc.
I can hardly believe that pliers left on the wiper could impact the windshield to crack it unless a fastball pitcher threw the pliers @ the windshield. Are you sure the glass chip was not preexisting. They can be hard to find & with any bump an existing chip can grow very fast.
I am not affliated with any local shops. I just restore old vehicles as a hobby & I have worked on fery fragile parts. In my hobby I have the option to let a part soak for months. I have even let parts soak for over a year to get the parts to free up. Your mechanic does not have that option. These issues are not always the case in a properly maintained vehicle.