Waited 2 weeks for the previous owner to disconnect, still waiting without internet

I tried to place an order as a new Virgin customer for broadband services and got an email saying an account is already registered with my current address, so Virgin won't be able to process my order. I just moved into this property as a tenant, so the existing account belongs to the previous tenants, who have moved abroad. I called Virgin and explained to them the situation. The first agent said she helped me to fill in a form, and I should get a response within 48 hours. That was a week ago. I kept calling every day and they just kept telling me to wait every time. 

How long do I have to wait while Virgin tries to contact the previous account holder? What happens if the previous tenants are no longer contactable? Do I have to wait until their contract expires, which might be several months or even a year?

I am considering cancelling the order and just set up services with another company but I am worried about Virgin charging me an exit fee.