Reliance Home Comfort

I changed my rental hot water tank from electric to gas. The contracted installer was competent and friendly. Tank worked for 2 days and then stopped. I've been without hot water for 5 days now and 3 Reliance technicians have come by with zero results. First technician came and concluded that the tank needed to be replaced. The second technician showed up with the wrong tank. His take was that only a part needed to be replaced. He scheduled a third technician. The third technician showed up without a clue as to what the issue was let alone the type of tank and what the issue was. He did not have the part with him. I've taken several days off work and am still without hot water. Apparently a new tank is being installed tomorrow. I was told that the window of time was between 4 and 8pm. It's fine for the customer to be constantly inconvenienced. How about reliance adjust to my schedule this once! So frustrated.