You didn't do anything wrong. I sell on Ebay and the question wouldn't have bothered me.

But I do know other sellers who take it as a warning sign when people ask even a simple question. And I understand that too from experience.

I've had perspective buyers start with a simple question then ask a ton more leading to wanting a huge discount. That might be what the seller was worried about.

But don't feel weird about it. Asking if something will fit your doll is not an unreasonable question. And as a seller I would've answered your question and not blocked you. His loss.

Ebay is just getting to be a strange and tricky place.