Apparently the latest update has a major bug where users are prompted after updating if they want to reset their stats. If you select 'yes', your stats are wiped. If you select 'no', you can't play the game. The only way around this is to reset your console.
It just beggars belief really how such bugs can occur and why updates aren't extensively tested. You wont see this in the likes of Overwatch, CSGO, Siege and other major multiplayer games made with the utmost care in their execution.
IW are a shambles.