Unable to Restore Purchase

I purchased the Photo Transfer app on 5/27/2016 (verified through itunes)
I've logged into the same itunes account on my iphone.
Launching the app and clicking the 'gear' icon and then selecting 'restore purchases' errors with:
'No Purchase Found' We couldn't find a purchase for this item. If you think this is an error please email us to: support@phototransfeerapp.com

Please advise