OK, so you have accidentally formatted a card that you thought you had backed up, how do you recover your files? For a start don’t do anything else with the card. If you record over the card your previous files will be over written and are gone for good. However data on a card that has only been formatted can normally be recovered.
One of the best tools to use is Disk Doctor Photo Recovery for the Mac and PC. Many users have report successful recovery of XDCAM files using this software.
On a PC many XDCAM users have reported success using Arax Disk Doctor http://www.disk-doctor.com/recovery_wizard.htm to recover the mp4 files.
Once you have recovered the mp4 files you should use Sony’s XDCAM browser to “import” the files into a new folder. This will recreate the necessary BPAV folder and correct file structure so that you can use the files.