These questions are always the hardest because everything you are saying is possible. Maybe they didn't change the parts or maybe they didn't notice the frozen caliper.
However, assuming they did change the pads and it is now worn out it would be due to a stuck caliper. It is hard to say that someone should have found that but it is something that should be checked by squeezing the piston back in and making sure it moves freely.
Again, from this information it is hard to know if they did something wrong or not. Sorry I can't be more definitive.
Friday, April 9th, 2021 AT 10:51 AM