Hello willkari.
I understand you lost your features for duplexing printing for your Photosmart 7525. Please follow this HP document on Printing on Both Sides of the Paper in Windows. This document will help you set this feature automatically or from the program you are printing from.
If you don't have a Windows computer, then let me know.
Also, let me know if this doesn't resolve your issue and I will continue to assist you further.
Looking forward to hear from you.