http://resolutioncenter.ebay.ca/
You need to stop communication with the seller now.
Go to the Resolution Centre and open an Item Not Received dispute.
The first step is to contact the seller. Since you have already done that, go on to the next step and escalate to a claim.
If the seller cannot prove delivery, and does not refund you, Paypal will, and go after her for their money.
Your feedback will probably be removed.
(BTW feedback is not the same thing as Detailed Seller Ratings. The former is public, the latter is theoretically anonymous.)
Do this immediately, because there are firm deadlines.
If you cannot open a Dispute due to those deadlines, go to the credit card you actually paid with (PP is just the mediator) phone the 1-800 customer service number and ask for a chargeback.