Our burner had been repeatedly going into lockout. Check Oil replaced two parts, and we experienced the same problem again. They replaced a 3rd part, and we had the exact same problem. Next, they wanted to replace a 4th part, which is where it turned into a negative situation. I expressed my concern that we had already paid for 3 new parts and labor, and nothing had changed. Although we did not think there was any malicious intent (the tech was very nice), it was clear that the replaced parts were not causing the initial issue. I asked if they would be willing to refund us for one of the parts (reinstalling our old part), and the woman on the phone became irate. "We'll come over there and take it back and never work on your boiler again. It's not our fault your boiler is s******* out." It continued to escalate from there. I calmly explained again that we didn't think anything malicious had happened, and i didn't understand this level of customer service. I asked to speak to the owner and was told he wasn't available, although she had previously stated that he was in the room. She said he would call me back to discuss. That never happened, despite leaving another message for the owner. Coincidentally our plumber was on site when we had this final call. We looked at the boiler together and figured out the problem was actually another part all together. In the past we'd had fairly good luck with Check Oil, despite some general flakiness, but this situation was unprofessional.