How to get into Privacy mode if fingerprint has now locked me out

[AC Question]

I put pictures in a private gallery with my fingerprint to lock it. When I tried later to access the pictures, the phone didn't get a good read on my fingerprint (I tried my print multiple times)and the phone is now asking for my backup password which I do not ever remember setting up. I have tried every password and pin I ever used and have had no success getting in. I'm thinking that I will never have access to that folder again. I did take it to a Verizon dealer and they set my phone up on some system (no idea which one) to set a password but that did nothing to access this private folder. Any suggestions?