Every ticket you buy through Fatsoma is stored on your account automatically.
You can access all of your tickets anytime at fatsoma.com/orders, or through the Fatsoma app:
iOS: fatso.ma/ios
Android: fatso.ma/android
Can't see your tickets?
If your tickets aren't showing up, the most likely explanation is that they were purchased on a different account. It's worth checking using the device and browser that you originally made the order on. This should help you see whether you have another account under a different email address. You create an account before you purchase your tickets so you'll never need to create a new account to access your tickets.