Hello.
I recently lost access to my first account, however, it's still logged in on my phone, because of this I've been trying to transfer my characters on the account onto this backup.
I'm aware of how to unclaim a character on PC however I'm unable to find it anywhere on mobile.
If anyone knows how to it would be highly appreciated 

In the campaign page, turn your phone sideways.

Turning it sideways is the same as the vertical layout but more spaced out sadly.

Even in portrait mode it should be visible:

I was using the App and not the website, that seems to be where the issue was. Thank you for the help!

Ahh. The app is designed specifically for offline use, so many real time features are not available on the app.