I went to my etsy, and under "Orders" on the left hand side was a link "Cancel an Order," which will take you here.
I relisted it first so that I wouldn't lose any information, then I went to the invoice section of the sold order and cancelled the transaction. I didn't leave feedback since I never heard from the buyer, but I did send her a message within the cancellation thanking her and telling her if she still wants a purse, to please come back.
I would think this is good costumer service. She may not have known how to buy and may not check her mail obsessively every day...like I do. I always like to give people the benefit of the doubt anyway.
SO now, the last thing I've done to finish this little unpleasant business is to cancel the invoice I sent from paypal. This I did by going to paypal. Under "Order Status" is a menu that says "remind." Click that and it'll give you an option to cancel.
Alright, now it probably really will take me several months to get a bite, but you know, that's business. I just want to keep making things, keep posting, and if someone thinks they're worth buying, then as we say in Oklahoma...YEEE HAAAAW!! :)