Dear Prudence,
My grandmother once had a diamond necklace that was a family heirloom. My grandfather, who didn’t know how to keep things in his pants, ended up giving it to one of his mistresses. My grandmother mourned the loss of the necklace until the day she died. Recently, I happened to stumble across the necklace, or what I think is the necklace, on eBay. I questioned my grandfather and contacted the seller, and both parties think it’s possible this necklace belonged to my grandmother. I wanted it back, but when I tried to discuss it with the seller, she said she was selling it for a reason and that, if I really wanted it back, I would pay her either the asking price or more. I am not sure what to do next. She has thankfully taken it down, but I feel like I am being blackmailed. Any thoughts?