Game save lost (almost 2 years of playing gone)

For the attention of someone at turn10,

I have played forza 5 for almost 2 years and i loaded up the game today after buying the car pass because it was on sale for £8 and after the game finished syncing my data it put me back to the start of the game. I lost over 14 million credits and over 200 cars and so much progress in completing every race in the game, is there any way I can get that progress back

If there is anything you can do to help me with this please do.