Keeps happening with all kinds of old baby stuff honestly, not just walkers. Cribs with drop sides, those old car seats from the 90s, swings, you name it. People hang onto it because it was fine for their kids and they can't wrap their heads around the idea that "fine" just means they got lucky. Your aunt's story is the part folks don't want to hear, because two babies in one summer at one hospital means it wasn't rare, it was just quiet. The seller calling you dramatic is really just him protecting his $40, which is a sad trade when you think about it. Best move is what you said, just report it and move on, you can't out-argue someone who's already decided.

Ugh, I feel this. I dropped Attack on Titan after 3 episodes back in the day and my buddy still gives me crap about it. Two years later I binged the whole thing in a week and had to eat my words.