Server not working

Mweb hosts our website which is a booking and registration site for a training company. Our whole business depends on this site working properly. Since the weekend we started experiencing problems with the booking site.Then it is on then it is off. Some sections on the booking site are no completly down and people cant register. We are losing money every minute that the booking site is down. I have now tried to sort this problem out with mweb since Monday and we are still offline. Apparantly mweb experienced problems with their servers the whole week. Not even once did any of the consultants told me that. They have escalated the problem to the engineers. They came back to us now and say there is nothing wrong but still we cant get in. I need this oroblem to be sorted out immediately. I have called and tried to call several times now without any luck. They keep me on hold and then they cut me off. I am now going to calculate my total loss in revenue for this week and i am going to hold mweb liable for these losses in my problem does not get sorted today.