When did you originally buy hosting with them?

Did you sign-up for the domain with them at the same time?

Right now you have a sub domain with them. Your domain is not active. If they have not registered your domain yet and it has been a significant amount of time you should break down and buy it through a reputable company like mentioned before. Namecheap is a great company for domain name registration. Even without support you should be able to get the domain running at least temporarily through their control panel given that everything on their end is working and setup properly.