WHY IS ONE OF MY SITES SUDDENLY NOT BEING HOSTED

My site www.insul8it.com is not working, I spent all day trying to find out what was going on and was told by register that the problem is homestead is not publishing it. I do not know how long it has been down because I have not checked it for a couple weeks. What is going on? I tried opening sitebuilder and clicking publish the entire site, but it is not not working. I have important bids out this week and my customers need to be able to see the site, this is a VERY big problem and I need help asap.