Craftsman 24kW Tankless Water Heater

We purchased this hot water heater last August from Amazon. The temperature was not being regulated correctly so instead of returning it to Amazon, I contacted craftsman and they sent me a new hot water heater. After a month or two, the temperature was no longer being regulated correctly. It would go from scalding hot to very cold quickly and I was scared one of my kids would get burned, plus showers were miserable, so I contacted craftsman again and after speaking with customer service, they sent me the same hot water heater, but went down a size. A few mornings ago very early. I was the only one up at my house and I heard what sounded like a gunshot and ran in to find that the hot water heater was heating water without being used and the water on the intake had gotten so hot that it melted the pipe and caused it to burst. Water was pouring out everywhere into my home and steam was pouring out of the hot water heater. Luckily my husband was home so he cut off the water to our house and the breaker before too much damage occurred. I’m so thankful that I was home this morning so my house did not flood. After like three phone calls to craftsman I am still waiting to hear if they will refund my money. I’m not asking them to pay for damages, just a refund of my money. I never want to use another craftsman hot water heater. All buyers should be aware that this is not a good product. I attached photos of the burst/melted pipe.