Once you've done this, you are ready to recover your lost farm!
* Launch the game
* Tap on the game settings icon in the upper left corner
* Tap on "Help and Feedback"
* Tap on "Report an Issue"
* Scroll all the way down to "Enter Recovery Code" and tap the button
* Enter the following code in the input field: VKBK C96U 9JZL and confirm
* Confirm that the name and level of the lost farm are correct and that you want to recover it
This should bring your lost farm back! :) And just a few tips to prevent this in the future:
* Make sure to have a Game Center and/or Facebook account, that is only connected to this farm
* Make sure not to give your iTunes and Facebook passwords to anyone
* Make sure to only play one farm on your device
If you have any problem or question about the procedure, do not hesitate to contact me!