You are being scammed.
The replacement will never arrive.
Don't listen to the scammer seller.
Escalate the Dispute to a Claim by asking eBay to step in.
If the seller cannot prove delivery (not shipping, delivery) you will be refunded.
If by some strange chance, the item does appear later.

you can return the refund using Paypal's Send Money service.
Oh and refunds take less than 24 hours and do NOT require you to close the dispute first. Two other common scams.