American Home Shield complaint: Plumber did not resolve issue – misinterpreted our contract coverage

We had a blocked toilet in the upstairs bathroom. The plumber assigned by American Home Shield turned up and tried to snake the toilet. He said that the blockage had moved up into the vent pipe and the only way to unclog it was to access the vent pipe from the roof. He said that was not covered by our contract and he left. We called out another plumber that same day, they diagnosed he problem, removed the toilet, removed the blockage and re-fitted the toilet. At no time did they have to access the vent pipe from the roof. So the plumber sent out by American Home Shield simply did not want to trouble himself with the job. But American Home Shield still charged us $100 for the call out. We also had to pay $615 to the other plumbers to resolve the issue when this charge should have been covered by American Home Shield as part of our contract coverage.