Lost significant game progress from the xbox synching with the wrong save.

Hey, so this has happened twice now. Occasionally I will sign into my friends xbox and play split screen forza 5. I’ll then sigh back into my xbox within a day and that progress is nonexistent. And weeks later it never caught up. And from a different instance this made 2 cars I had simply disappear(800k worth). These cars weren’t even cars bought on his console. I even currently have a saved design for one of the cars that disappeared. What I’m hoping for is that I can be reimbursed in game tokens or credits to account for this problem. Otherwise I am just going to have to be done with Forza because there is no point in gaining progress if it can just be reverted back an earlier save so easily. Any real help that would get back what was lost would be greatly appreciated.
Thanks.

Make sure you recover your gamertag when you log back in to your own Xbox One.

Also, check this information about your One being a “Home Xbox” or not: Xbox Support

If that doesn’t help you, I would contact Xbox Support and have them describe the correct method of synching up your game save when you’ve played on a different console.