And it continues...
Loosely translated: "I sell shit too, and I hate when buyer's try to game the system. By the way, I'm going to game the system so you better take a return because 'MURICA where I'm free to be fat, unlike them skinny Asians."
Where the pictures of two separate tags both displaying the word CHINA not clear enough? Sounds like he really just has remorse for supporting overseas goods (because he's a capitalist and not some socialist liberal pansy of course).
*edit again* Any suggestions for replies welcomed. Thinking about just telling him that I'm unfamiliar with the return process and would like to follow official channels so would prefer if he could open the case. I'll fight this one, Brian, don't like being extorted like this even if I risk my 100% feedback. $50 was fair market value for the shirt, so doubt I could score a major win by relisting anyways.
I would definitely give eBay a call, as Brian suggested before moving forward in any form. You need to know the risks involved in fighting. If eBay says they will win, fighting sounds great in principle but results in you losing your money and the shirt. Is losing an additional $30-$50 worth it?
Does True Religion post measurements to their sizes? Maybe reply stating that you listed the size correctly and that if he buys brands he has never worn before that he should have checked their size chart.
Here is a link to their size chart. It doesn't have a 3XL, but does show a 2XL to be 44-46" chest measurement.
With that said, I have added a disclaimer stating that I do not accept returns for improper fit. If they want to make sure it fits, ask for measurements. I wonder if that would help eBay decide in my favor, but it should scare buyers away from trying. This guy sounds like a scumbag and I hope you win if you fight it.
Edit: I have found the best deterrent for returns is to actually have a return policy but charge a crazy "re-stocking" fee. I have had a couple of people make bogus return requests and luckily, after explaining my policy to them (them paying return shipping and the crazy additional fee) they just don't reply or return it.