Website is missing from the server.Losing money

The whole week we had problems with our booking site. We called mweb several times. They were not able to assist. Today our whole website which is a booking site disappeared. Our whole business is run on this booking site for customers to register for courses. When I called mweb they told me they cant see our website anywhere. It seems like it just disappeared. Nobody can help me and i am losing customers and sales by the minute. They say i have to wait until Monday. This is totally unacceptable. They say we are on an old server and the server cant accommodate us anymore. Apparently they tried to move the site from one framework to another and in the process we lost information. Another one told us that the mweb server has crashed. I am going to hold mweb responsible for any losses . This webiste cost me over R 500 000 to develop. I will also hold mweb responsible for the advertising costs that we incurred today to advertise on national television. We are now looking like total fools. I am also going to post this on ecery social media platform if i don't get assistance NOW. I want my webiste back NOW!! Please call immediately so that somebody can assist me urgently. URGENT PLEASE