Easy.
Never accept an offer of a replacement.
Money only.
Then if you still feel confident in the seller, you can re-order.
There is no reason to believe that a replacement will be any better than the unwanted item you got.
There is no reason to believe that a replacement will ever arrive, when the first one didn't. In fact there is no reason to believe that the seller has anything to sell at all.
Waiting for a replacement puts you past eBay's Dispute deadlines. In some cases it can even put you past Paypal's six month limit.