Possible Shipping Complaint Against Me, What Can I Do

First off, done with .99 cent starts. Sold 10 items to 10 different people a couple Sundays ago. One still hasn't paid me. One is complaining about shipping issues that are beyond my control.

Some of those items were BIN stuff that I made money on. Probably because the low start auctions drew attention to my items. But over all, not worth it.

I'm worried I might get bad feed back due to this situation. And I'm new to this, don't have a lot of overall feed back. So one highly negative could really hurt.

Buyer won the item on Sunday afternoon (18th). He paid for it Monday afternoon(19th). After my postal carrier had already gone by. Put it in my shared community outgoing mailbox.

Carrier picked it up Tues afternoon. My local post office processed it that night(20th). One day after he paid. So I'm well within the tolerances of when ebay thinks I should have it to my PO. They had it to the regional post office in Cedar Rapids by Wed the 21st.

He sent me a message the 31st wondering where it was. Got that on the 1st. Ebays latest update was Cedar Rapids on the 21st. But knowing the USPS site is always more up to date, I checked there. Item was checked in at the Detroit regional center the 1st. 10 days after it got to CR

Why? No clue. Ebays own site warns in the label printing area that the USPS has slowed down considerably. But on low cost items no one is goin to want to pay the $15-$20 it would take from my area to use Fed Ex or UPS, or even $9 for Priority express.

Maybe it's the flood of mail in ballots. Maybe it's the new Post Master cutting overtime. Maybe it's lots of postal employees out with the virus.

I let him know that because I print my labels from ebays site, the tracking number always shows up in the sold item details. And that ebays info is slow. And how to take that tracking number to the USPS site to get the most current info.

Also gave the same examples of why the USPS has slowed down. Only after I sent the message did I realize he's a coin seller too. And uses USPS. Although only a few coins listed and under 40 feedback.

So his message back to me was that he took my advice as condescending. He has never had a coin take more than 5 days to get there. So I must have done something wrong. Asking if I had gotten the coin to the Post office in one day? Even though I spelled that out in my email, and he could easily see that in ebays tracking.

So, long story short? If he leaves negative feedback, can I defend myself? Will ebay consider removing it. Since the timeline clearly show the post office messed up. Can I at least post a response? Which sucks because few people take time to read why you got negative feedback.

Sadly ironic part. The item he bought from me was a 1964 Mexican mint set. With the one peso coin that is 10% silver. I don't list those as silver, cause it 90% not silver. But guess who has a lot of them listed as silver. No mention of 10%. I'm sure he'll resell what he bought from me with a misleading listing. And yet I'm the one who could end up with the negative feedback.

BTW, anybody know if ebay has regulations on silver percentage? Can he list those as silver?