Holiday Heating & Cooling

I recently had Holiday Heating & Cooling out to my house for AC service. The technician was on time, friendly, knowledgeable and got right to fixing he problem. Their Diagnosis charge was $85.00 and they replaced a motor start capacitor for $135.00. The AC was back working within about 20 minutes. I have no problem with the quality of their work or the $85.00 diagnosis charge, but a quick search on the Internet showed that my $135.00 part is readily available for less than $12.00 shipping included. This markup seems quite excessive to me. I called the Sales Manager at Holiday and told her about my positive experience but that I thought that they had overcharged for the part based upon the Internet price. She declined to make any adjustment of my bill.