If you had previously saved via Facebook against this profile, a save conflict will appear displaying your old progress. Switch this to your old save to continue from where you left off. You'll see a button to log in with your Facebook account in the leaderboard screen every time you finish a race.
If this doesn’t help, then can you please send us a message with the following info:
- Your User ID, which can be found on the game's settings menu.
- When did you lose your save data?
- What did you lose in terms of vehicles and upgrades?
- Did you make any purchases from the store? If so, provide us with a copy of the order receipts, please.