My gas water heater broke down in August. The plumber said he could fix it, and meanwhile, disinstalled it and fitted another that he had lying around. This was fine in August when it was warm, but the replacement (which is a much older model) doesn’t have the power necessary to heat water in cold weather. He texted me in September to say he’d fixed my original water heater and would be round in a few days to install it. No show. I’ve been ringing him and texting him since then, but after giving me a few excuses (poor health, very busy), he stopped replying. I’m fed up of cringing with cold while showering and have decided to get a new water heater, installed by the seller. Would I be unreasonable to refuse to pay the first plumber anything for his work (installing an older model, repairing my heater but not installing it) in the event that he eventually gets back in touch with me?