Unlike your Zedge free favorite and download items which are linked to your signed in Zedge account, at present, your acquired and downloaded Zedge Premium wallpapers, ringtones and content items are linked only to the device in which you unlocked them.
More specifically, it's tied to the AppID/UID created for you when you installed the app on your phone or tablet.
This means that if you uninstall and reinstall the app on the same device, or clear out app storage or begin using a new phone you will no longer see the Premium items you've previously unlocked.
If this happens, in order to help you, we'll need your original app ID and your new app ID. In the case you have replaced your old app on the same device, this will not be possible.
However if you have upgraded to a new phone, you'll be able to send us the old appID and the new app ID. We should be able to link the new device to the previous appID.
How to get your appID/UIDs
iOS - click the Contact Us -> Support Questions link in iOS (to firstname.lastname@example.org)
Android - click Help -> Feedback -> Send Email (to email@example.com).
These links automatically grab the necessary ID from the app and puts it into the body of the email).
Note also, the Zedge apps do not currently support using the same account across multiple devices -- though we hope to improve this in the near future.