Campbell Appliance Heating & Air, Inc Overcharged for parts Round Rock Texas

My AC went out on a saturday evening.  On Sunday we called the company and were informed it would be an $89 dollar after hour service charge plus any parts.  The technician arrived quickly, confirmed the capacitor was not operating, and said he happened to have 1 on the truck he could have on in 5 minutes.  The charge for the capicator was $329 - a huge markup for a part that costs around $20 or less. He assured us this was the company's cost and the reason it was so much was it was a 60/5 MFD.  This of course was not true and no company should employ that kind of markup.  of course we paid, we were already out the service call and it was a sunday projected to be over 100 degress.