Greetings jeggott,
I see that you are having an issue with the Call of Duty mobile app updating. Where did you join the new clan, on the mobile app or in game? Does your in game clan detail show the correct information? When did you switch clans? Have you tried rejoining the other clan? Have you attempted uninstalling and reinstalling the app? Can you try logging in to the Call of Duty website, unlinking your online id, clearing your web browser's cache and cookies, relinking your online id, and playing a multiplayer match?
Thanks,
^AJ