It is not uncommon to have different buyers with the same address. Some are legit buyers, others are using this address so the tenants in that house serve as intermediates for reshipping purposes.
For the way they asked you the question, it seems they are foreigners or recent immigrants lacking the English language skills.
Block them, send them to your "mystery list of buyers" 
But Ebay should not be giving you the square peg solution for a rounded problem.
@hillbillymedia wrote:If your #2 happened exactly as you stated ( I am NOT implying it didn`t) it should be an outrage to all sellers. We either have rules, procedures and time frames on this site or we don`t. Here is a link to the unwelcome/malicious buyer policy. I`d learn it and quote it to customer support. I`m assuming you have already blocked the user ID`s. https://www.ebay.com/help/policies/selling-policies/unwelcome-malicious-buying-policy?id=4375
Yes, I have blocked the user ID's, but again because guest accounts, that isn't really going to do any good. on Order # 2, here is the exact chain of events.
Order was placed on 1/25/19, shipped on 1/28/19 with UPS ground going from one side of the country to the other (usually about 5 business days).
Return request was opened on 2/5/19 - Doesn't match description or photos -"Nothings came whats going on ".
Tracking shows "Recent weather has caused delivery delays. Recovery efforts are under way to deliver your package as soon as possible." We sent multiple messages to the buyer with the tracking info, alerting them to the weather delays and letting them know the package should be there soon.
Package was delivered on 2/6/19. We sent multiple messages asking buyer to confirm they received it and got no response.
2/7/19 - We authorized the return to avoid a ding for not responding, choosing the option to have eBay bill us for the shipping label. Then, we waited. No tracking number was ever uploaded in the return and there was no indication the item was on the way back to us. The return case showed that if we don't receive it by 2/15, we can call eBay to have them close the case.
2/15/19 - Called CS to have case closed (this was before we realized this was the same buyer, so reason for closing the case was just that they had not yet returned the product.) CS said they were closing the case in our favor and at 12:52 PM Eastern time on 2/15, we received an email from eBay stating:
We reviewed this case and have closed it without any refund to the buyer.
The case will not affect your seller performance. Any feedback left for this transaction will be removed. The buyer did not return the item to you within the required timeframe.
About an hour after that, we received the return request on order # 3, put things together and made a call to Trust and Safety as well as reported all 3 buyer ID's through the online "report a buyer" function.
We are closed on the weekend, so I didn't actually find out about this until today - Received a message dated 2/16/19 from eBay stating:
eBay Customer Support has reviewed the case and made a final decision.
We issued a full refund of $39.98 on Feb 16, 2019 to the buyer. As described in the eBay Money Back Guarantee, the refund includes the purchase price, plus original shipping. This amount will be deducted from your PayPal account or charged to your preferred reimbursement payment method.
Decision:
This case has been decided in the buyer's favor.
Comments:
Unfortunately, it looks like the refund you agreed to issue was never sent to your buyer. We've issued it and now need you to reimburse us.
When I called CS, they said the buyer provided a tracking number that showed delivery to us on 2/15. We don't have the package. The tracking number CS says they gave shows delivery to our zip code, but "left at front door", which wouldn't happen at a commercial business address. And I just now realized it shows being shipped from GA when the buyer is supposedly in CA. So, I guess it's time to call CS again. 
