I would say the shop screwed up when they installed the pedals, therefore their responsible for repairing it.
My 84 Trek 660 commuter/former racing bike/training bike/fitness bike/credit card touring bike, is extremily dependable and still is after 150,000 miles. The only part I ever had failed on a ride (fortunately it failed about a mile from the house), was the front derailleur band broke for which I had a new Superbe in a box stored for such an event. Of course I've had the usual flats on the road, and of course chains and gears wearing out but those are replaced as needed, and the occasional crash that led to bent wheels or a broken spoke (which never caused a problem either with 36 spokes, I just wrapped the dead spoke around another and rode home).