My 2015 Toyota Prius (85,000 miles) had a ceased RR brake caliper. New caliper, pads and rotor were installed. Was it necessary to replace the LR pads and rotor given new pads and rotors were installed all around less than 15k miles ago? There were no issues with the left side.
Does your car pull to one side with hard braking?
No, it did not.
To answer your question, No, you probably got ripped off.
Probably not but you have to look at what they quoted for the repair. Once you sign it's on you. They probably quoted a brake job which is everything not just the parts that actually need replacing. A lot of places insist on the doing all four wheels. One frozen caliper would mean they would have to trouble shoot the brakes. Most are to lazy to do that. Besides they make more money that way. Sounds like a warranty issue with the shop that did the last brake job.