Can't figure out how to use multiple devices

[crimsonDestroyer]

I have two devices; a phone, and my PC. I want to be able to use one account on both, but it seems impossible. If I'm logged in on PC and try to set my Chumhandle on mobile, it just doesn't work. If I'm logged in on mobile and try to log in on PC, it says my Chumhandle is taken. I've tried everything. Nothing seems to work. Help?????