incrediBILL - 1:30 am on Nov 1, 2012 (gmt 0)
I hadn't considered a file recovery program but that's a good idea.
Couple of issues I see is:
a) if they've replaced the index file and the server is creating server logs and/or processing email it's already busy obliterating files and should be turned off immediately.
b) if it's a rental server the host may not be willing to pull the drive and hand it over, certainly not without charging for the hardware.
c) the time involved before getting a site back online could be quite extensive
It's not even as though I can reinstall a CMS or anything as the system was customised and intracate.
I find it hard to believe that whoever did the customization didn't maintain a local copy.