A buyer can request a seller's details by requesting them from eBay.If she did then you would have got an email from eBay about that.

eBay has the Money Back Guarantee,so it doesn't really matter if your listing states "no returns".

Best you be reading the MBG details as they are on every page & every listing.

Your buyer opened a case by hitting the big blue button next to every item bought "Return This Item"

Keep all ebay messages from the buyer & they may also read yours to her.