How to keep a home in foreclosure with no paperwork

[Leah Ezra]

My parents separated in 2012, my father was the one to initially leave. When he moved out, I lived with my mom in our family home, but eventually she moved in with her new partner. At the time she decided to move, she offered that I either move as well, or keep the home and pay rent to her. I chose to pay rent and stay. I am still in the same home, now living with my husband and 3 dogs. This home isn't where we intend on staying for the rest of our lives, however, I feel like letting this home go would be silly. The house has been in foreclosure for going on 6 years this August (I believe). We have a feeling that the bank has lost the deed/paperwork to the home. I am curious what measures we could take so that we can guarantee our home won't be taken away, and we can own it free and clear.