Feedback is your leverage in this negoitiation. Figure out what price you would have paid for the damaged goods you now possess. Request a refund for the difference, or a replacement if you're not satisfied with what you've got. If necessary, you can go through PayPal to get your money back, but then you'd better not build them up, and it can take a month or so. If the seller makes it right, it is a positive. If not, you're dealing with the feedback dance as others have mentioned.