Sections of my realm have been converted back to the original landscape

My friends and I got on our realm today only to find out our base is ruined, multiple areas of it have been converted back to the original landscape it was when we first created the realm. Our builds and progress have been lost, I tried restoring it to a backup from yesterday but it didn't do anything. Many of our chests of supplies were deleted, how can we restore it back to the way it was?

Thanks