We (Astraware - the makers of the games!) can't usually help with anything that's to do with your purchasing account.
The usual problems people ask us for help with on these are changing email address, and updating credit card details.
You'll be able to get help with these things directly from the App Store associated with your device - here's a set of links to some of the main stores :
Barnes & Noble NOOK store support pages
Apple Support Pages
Google Play Support (Android)
Amazon App Store (USA)
Amazon App Store (UK)
If you can't find what you're looking for - let us know, we might not be able to fix it for you but there's a good chance we'll be able to point you to the place, team or page that can!