I've had to use charge-back a couple of times. Once via PayPal. It worked both times. Neither time did the 'trader' (ahem) reply. But I got my money back and left appropriate reviews on TrustPilot....Also, it's not like fresh new refunders don't crop up regularly...
Source: https://www.reddit.com/r/starcitizen_refunds/comments/vi71s3/i_made_the_mistake_of_purchasing_this_game_now/
One tip: record everything in emails that you send to the