I agree with Ethel on this too - ebay is completely run on trust and without the trust there is no business.
I still say be calm about ti, raise the relevant disputes and wait and see. If a paypal claim is settled in your gain, then you can do what you want with the boots as there is no obligation to return them. If you paid by some other means, you may just loose the money, but kick up a fuss with ebay and leave the usual negative feedback.
See what else she is selling, it could be very telling!!