The problem is, we cannot overtake laws.
And in pretty much any country, laws grants consumers the right for refunds. No matter what.
Doesn’t matter what rules Epic gives to Marketplace, all major country has consumer protection and regulations; Unless Epic has 100% proof that the product is flawless they are forced to send back the money. Just give up on this one.
Even if 100% flawless, consumer still can refund if wish so.