Sims data is deleting itself

My sister and i have been playing sims as long as we can remember. Between the both of us, hwe have bough nearly all of the packs. Whenever she plays and i help her make characters and houses and stuff, it doesn't always save. We have uninstalled all of the packs and game base a few times and redownload them but it doesn't load. It doesn't say its corrupted BUT its like the entire things deletes itself. We would only have 2 or 3 small families (then leave any sims thats already in the world) and play. But after like idk 5 or 6 hours and we save it to play something else, we'll come back and it wont show up. How can we fix that? Be mindful. We had tried uninstall, unplugging the Seagate after turning it off, restarting and even factory reset just incase and still nothing. Should we try on another xbox? Or try another Seagate?