My mother pawned her ring that she had appraised a...

My mother pawned her ring that she had appraised as a 1920s 1.2 karat diamond because she needed grocery money. When we came to get it 6 months later (she got an extension) it was a different ring that looked alike. She had the ring since she was 18 and it has been in the family since the 50's. She told them it wasnt her ring and they said it is because its still in the envelope they had put it in when she pawned it, she didn't believe them at all but they kept denying and she isn't a jewelry expert. She never felt the same about the ring again so when I needed a car repair we took it to a jeweler and they said that it was a 1 karat diamond from the 1960s. Im so pissed this day but its been 2 years since sold and 4 since it was pawned so I just feel like is they can do that to my mother who knew the people who worked there for 23 years and my grandmother has known them since the early 90s. My family has sold them ww2 era m1's and a 1911 we got when my grandfather died and made them alot of money its so scandalous. I hope they are arrested or a investigation be brought against them.