Just escalate now. If she can't show through Delivery Confirmation that those eggs were delivered to your address (which she has if you paid through Paypal, assuming that your address is correct on your PP account), Paypal is going to side with you. I think she is just stalling, hoping that you will give her the benefit of the doubt and drop your claim. You don't want the eggs now anyhow, so there's no point in letting this drag on.