Game dials back by itself

I have an issue with Forza Motorsport 6. This is my 3rd day playing and twice now the game has dialed itself back near the start. I lose credits I’ve gained, mods I’ve brought, cars I’ve won and brought, upgrades I’ve done to my car. I’m getting annoyed at having to redo the same races over and over again. I can’t win the same cars in the spins that I had which means I can’t do the races I was doing. The game did an update today before I could play and it seems it took me back near the start. It’s fine whole playing but when I return the next day all my stuff is gone again. I spent heaps buying some mod packs and even they disappeared so I tried buying some more and of course they are all different. And for some reason when I play Forza 6 or Forza 7 it signs me out in between races so the game restarts, I don’t have this issue with any other games. As it was the game installed and I had been playing it and then yesterday it made me install it all over again. Do you know how frustrating it is having to do nearly 50gb twice for no reason? How does the game just delete itself of my xbox after I have installed it and been playing then come back the next day and ‘BAM’ I have to install again. Luckily today I haven’t had to re-install but I still have to do the same races I have done. It’s hard to progress through a game that keeps dialing itself back on me. Considering it auto saves I shouldn’t have this issue at all. I see the save symbol after each race so how is it that my savedad game is magically dialed back? I want some answers and something for my troubles. I had cars and credits that I earned with my hard work using my G920 and ‘poof’ they’re all gone.