Homestar Heating & Air Conditioning Inc

My furnace broke down twice for the same problem with 2 service calls to HomeStar within 1.5 week period. I had to call them for service since my furnace is still under 10 years parts warranty (installed by HomeStar).
The first service call for my furnace was on April 07, 2018. It was a burnt out control circuit board (under warranty). Service technician said that I need to get a maintenance service done ($150) which was a 10 min vacuuming of the inside of the furnace, in order to have the parts warranty granted. Labor cost for replacing the circuit board was $375. Total cost was $525.
On April 16, 2018 (1 week later), the furnace failed again. Same technician came in. He started replacing other parts since he did not think that the control circuit board he replaced a week ago was defective. He replaced the flame sensor, then the blower. Finally, he replaced the same control circuit board that he put it a week ago.
I was charged with $214 on this 2nd service call, being told that it was the labor cost for replacing the frame sensor. I asked why I was billed for this while the problem was a defective control board that he put it a week ago. He told me that the sensor was old and could be broken anytime soon.