So, you have backups of what you cannot find? Why don't you just restore them? I have no other suggestion for you because I don't know what the BB guy did and neither do you unless you call and ask or take your computer back to them.
If you have a full Time Machine backup, system and all, then just erase the drive and restore the backup.
Install or Reinstall Lion/Mountain Lion from Time Machine Backup
Be sure you backup your files to an external drive or second internal drive because the following procedure will remove everything from the hard drive.
Boot to the Recovery HD:
Restart the computer and after the chime press and hold down the COMMAND and R keys until the menu screen appears. Alternatively, restart the computer and after the chime press and hold down the OPTION key until the boot manager screen appears. Select the Recovery HD and click on the downward pointing arrow button.
Erase the hard drive:
1. Select Disk Utility from the main menu and click on the Continue button.
2. After DU loads select your startup volume (usually Macintosh HD) from the
left side list. Click on the Erase tab in the DU main window.
3. Set the format type to Mac OS Extended (Journaled.) Optionally, click on
the Security button and set the Zero Data option to one-pass. Click on
the Erase button and wait until the process has completed.
4. Quit DU and return to the main menu.
Restore from backup: Select Restore Time Machine backup and click on the Continue button.
Note: You will need an active Internet connection. I suggest using Ethernet if possible
because it is three times faster than wireless.