I understand being annoyed at a sales pitch, but this sounds like about 3-4 hours of work for the contractor, which comes out to about $80/hour. That doesn’t sound so unreasonable to me.

Sorry, I skipped some details. They had a pre-agreed $180 "diagnostics fee", which we paid, then they tried to charge $250 on top of that for the part. The contractor had no technical knowledge and kept video-conferencing the office for help. He had lots of sales training, though.

Even trying to sympathize with the contractor is ontologically evil.