The backups were not done correctly and so when the host restored the site after a failed update attempt, all data was gone.
He can recover of course, its better to have this happen now and learn the lesson than to have it happen down the road when your site is larger and busier.
Let this serve as a lesson to everyone,backup your own stuff, do not rely on your host to do it for you. Back it up and download it and get it off the server. If your host sees you have 25 backup files on the shared server they are going to get upset. So get it off the server and on your pc in case the server crashes.
I learned my lesson many years ago i kept my backups on the server and guess what, the disk crashed on the server and i almost lost everything. I had to pay my host $75.00 to restore my site from a previous backup they had on file. That was the first time and last time that happened.
Backup your stuff, keep it local, and you will be just fine if something happens.
Dave :)