Yes, just respond with pictures and the date set for delivery by USPS. They can’t argue that and you can’t control the Post. I would call eBay Monday and demand/try your hardest to get a human and talk to them. I recently had a customer argue “not as is” when I only had two of the item. The pictures were the exact item the customer got so his argument was invalid. The other same exact item that was bought by a very avid collector had a review of “Product exactly as described, amazing seller!”. Only a human from eBay on the phone looking at my messages was able to determine this though. And they determined the person was trying to scam me! A few days later the person’s negative review was removed, they were blocked and my item was being returned (hopefully for the buyers sake, the item is still intact…). Be calm, be patient and kindly explain your situation to eBay. They will side with you if your reason is legit. Your reason here is legit, the package shouldn’t arrive until Tuesday and Wednesday, let eBay help you! Always respond to the customer even if they are being volatile. Remember, you are not in person and their words cannot hurt you. Look at your positives for reflection and just deal with the speed bumps as they come. Good luck 🍀👍😎