I just want to thanks everyone volkiller730 Noga —
I didn't change anything but now it's fixed so I believe it was just an error in their automated system
You can read about tablet support here:
http://developer.android.com/distribute/essentials/quality/tablets.html
I used the contact form at the bottom:
https://support.google.com/googleplay/android-developer/contact/tabletq
And today I received an email explaining that the app meets the tablet app quality checklist to be considered designed for use on tablet devices
Have a great day!