You are using domain, but You don't have any control of this ? I don't know details (looks like someone stole this domain), but if so then this looks quite stupid, because You have given all possibilities to blackmail. If You still have access to SQL then first of all copy all tables. Installing a new shop is not so hard, but lost all data is very annoying. After database copying can think, maybe it is worth to try with some other domain. But then again, I don't know details.