Whatnot Doesn't Want to Refund Bricked Item

So a week back or so, I bought an DSi XL on a stream. The problem that I experienced is that the streamer in question changed the description of the item during the stream (I've noticed they do this a lot lately). First they said that it had trouble launching the camera. So I thought it'll probably work for games. Then the description changed to it can't launch most apps, and finally ended up being described as bricked. So I requested a cancellation, the seller rejected it without an answer. I asked Whatnot to cancel it and said they couldn't do it because it's their policy to intervene until after it's with me.
The item arrived on my PO Box and sure enough, the item was bricked.
Whatnot support made me ask the seller first for a refund and their answer was that they said bricked before the item ran, I can't personally verify this but even if that was true, why did the description change during the stream?
Anyway, Whatnot asked me to take photos and make a video describing my issue.
So I do, and they tell me that they'll refund me the item after I return it.
They send me a USPS label and said the item must be shipped within 5 business days (Support by mistake said that the item should be in their warehouse in those 5 days, but was later clarified).
The problem is that I don't live in the US, I live in México and USPS (United States Postal Service) doesn't work here.
I told them as much and they pretty much said that I either sent the item in 5 days or I wouldn't get a refund.
I sent them another e-mail explaining to them why their solution couldn't work for me, and after two e-mails they finally replied that they needed me to explain why it didn't work.
So I had to walk support through all of this in a handful of e-mails. (Whatnot does ask you for your country of residence, so I was a little confused why they all seemed surprised by this)
Their latest response was that I should pay for shipping, and that they'll later give me that money back in Whatnot credit.
To be honest I found that solution to border on insulting and I'm considering asking PayPal for the refund directly.