No phone line and no help either!

We are a small business who rely heavily on our phone line. Our phones went down on Thursday last week which we reported immediately. It is now Tuesday and nothing has been done. The call center tells me I will be contacted when a technician is allocated the fault. Well I haven't been contacted and I still have no phone line. They cannot give me the number of the technical division or a technician as they say they don't have them. They cannot tell me when someone will assess the problem or when the problem will be resolved.