Happened to me too, in both situations. Once I sold a vanya silk for a zero too little, asked nicely if I could buy it back at double that price, was ignored. The other time I sold a Spring Dress at a zero too little, asked nicely, and was actually given the Dress back in exchange for crafting them one in exchange for their own materials - very nice person, that one.
A few days ago I bought a polarized glass for 10k something.