International Returns as Buyer? Seller won’t cover option for tracking & insurance

Bought jewelry off of eBay a few weeks ago from a seller in Japan, and seller sent the wrong size. Now I’m trying to return it as I have no use for it and it was $200. But the return process has been a pain. :(

Packed up the original box and took to USPS and was told price was $55 w/ tracking and insurance! (box is like 6x6x6ish and 6oz) This seemed crazy expensive, so I told seller, but they used online shipping calculator saying in an envelope it would be $13.23. I have to repack it (fine) but that option doesn’t have tracking or insurance. But I’m afraid seller won’t cover more then 13.23.

So if I ship in an envelope now, with no tracking or insurance, how risky is that for a return and getting my money back? If it gets lost I’m assuming I’m shit out of luck, or seller could claim it never arrived without tracking info right?