Baby Powder Trick? I do not know about this one...
Sorry about your fowl transaction. Something similar happened to me with Neige d'Antan: one or two stains were mentioned in the listing, but when I got it the christmas-y bias was full of food stains, very hard to hide. And pulled threads as well. It was obviously worn for Christmas dinner (or lunch). And because of all the things going on around the holidays I forgot to contact the seller. The stains were only faint after a nice bath in my sink and I got it way below retail...
Someone taught me this: if it's an oil based stain as quickly as possible cover the stain completely in baby powder. Let it sit overnight. Usually a few hours will do. Then shake off the powder and wipe any residual with a soft cloth. That has worked for me several times to lift off oil stains even when they were old. It's a very good trick to remember for table linens.
Sorry to hear about your bad experience, it seems like we have all had one or two, this one was an expensive ouch.