Please tell me that you hadn't left her feedback first and that it was positive? Because when the seller leaves feedback first it doesn't leave any area for negotiation if the buyer is displeased. They neg and move on, happy as a lark that they have left you what they feel is your due and you can't do anything about it.
Feedback is not the place where a seller should be notified of a problem with the outcome of the auction.
How many feedback does the seller have? There are new rules and regs in regards to feedback from newbies. Newbies don't understand the ins and outs of selling online and sometimes, yes, sometimes fly off the handle. <blech>
Can you explain your case to her once again and then file for a mutual withdrawal? That is of course unless you haven't left feedback for her.
Good Luck,
Donna