Just got off the phone to EA after complaining why I don't have any access via the Web App.
One of the things he said their system looks at a factor for why players don't have access is to do with games not finishing. Personally mine's at 99+%, however I'm not sure if this applies if your opponent leaves early to how this works?
Mentioned other usual stuff to like stop hackers and to give everyone a fair chance at playing Ultimate Team so for people in the past that have generally been 'active', that's another factor that may weigh against you getting access.
Just really a thread for info to give you guys a chance at working out some more stuff. Don't worry I've said I'm not happy lmao and taking it further.