Continental Roofing - Point Roberts, WA

I live in a 5 years old row home with a narrow roof. One day I got a leak from the ceiling of my upper level bathroom. Contacted my strata who sent 2 contractors from Continential Roofing. They came and decided the roof was too frosty to climb onto. So they sat around in the parking lot and played on their phone while waiting. After 2 hours or so, they started their inspection by climbing up onto the roof, and into the attic. The whole process took less than an hour. They couldn't find any problem and no repair work was done. I was backcharged for almost $550 for the job. I don't understand why it is so expensive. There is no repair work done at all. One of the two guys sent did absolutely nothing. The actual work was completed in less than an hour. If they charge for travel time, the company was not far from our home. They chose to come at that time when there was frost on the roof. They chose to stick around and wait for the frost to melt. Why am I paying so much for <1hr of actual work?