This app may not restore to a new iPhone

I originally purchased this app in 2010. When I updated my iPhone in 2012 the app did not restore. I repurchased the app because I use it for work. It did restore in 2014 when I upgraded to iPhone 6. Then in 2015 when upgraded to iPhone 6s App did not restore. Apple says purchase does not qualify for refund.

Qkatt about HP 12C Financial Calculator