Cannot restore from managed backup

riverdentistry.com got hacked and I tried restoring from downloaded managed backup and standalone snapshot file, that did not work and the snapshot file caused errors. When I was able to get into the site, I tried restoring from managed backup and that did not work either. I also could not import a managed backup file into snapshot to restore. The hack actually might have been helped by the fact that a couple days ago I tried to create a managed backup, but instead of server backup it created a local backup in the website file structure. Since I backup users table only to remote backup, chances are, hackers were able to sniff it and use it to login. Is there any way to prevent that in the future? Thank you for your help. M.