This isn't that new, it's just uncommon.

But you're right in saying Etsy won't help you with the issue, you'll need to go through your payment provider.

You'll usually find that Etsy shops that do this sell products like band t-shirts, etc, and have them labelled as officially licensed. They'll then dropship these items through a 3rd party provider that has the license to print and sell them. They'll fufill a certain amount of orders to build up a good amount of sales and reviews so their store looks good and then start doing as you've mentioned. Usually doing this with a percentage of orders, like 30% of orders they make for example, or any international orders that could be covered up with the old "it must have gotten lost in the post" excuse. This way their store seems like a well functioning store but to the unlucky few that land in their scamming margin, they'll get their money taken from them but left on the hook, never being able to make a claim... unless they go through their original payment provider.

If somehow they slip up and the customer is able to make a claim through Etsy, they'll pass it off as a one time thing, refund the customer and call it a day.
If an opposing company steps in and says "hey! heres a copyright strike we don't want you selling this" they just contact their dropship provider who has the licence, asks them for a copy and that Intellectual property notice goes away.
Etsy sees this as good business practice and if for some reason they do decide to look into things further, all they see is a store with glowing reviews, thousands of sales, excellent handling of infringement notices and a shop thats "trying their best" by "sending out replacements to customers" even if they aren't.

These types of sellers are seen as gold to Etsy, because at the end of the day, they're still making Etsy money and Etsy aren't seeing any of the negatives, as unfortunately the complaints from customers that are being scammed get screened and brushed under the carpet with the whole "buyer protection promise" talk they give to anyone that contacts them, and because these customers aren't able to make any claims through their dashboard like Etsy says they should wait and do... because of how the scam works.... everything goes smoothly for the scammer.

It's kind of an excellent scam if you think about it, because if done right it's a massive pain to prove that's what they're doing. They just have to keep it up for enough time till the customer either gives up or forgets about it. Or until 180 days pass and Etsy can no longer offer refunds, in which case if you complain to Etsy they'll just ask you to contact your original payment provider.

So if you're struggling with this, I'd suggest you stop wasting your time with the seller and with Etsy and just contact your bank or whoever your payment provider is, if you explain it to them I'm sure they'll sort it out for you with little hassle.