The dev response was poorly delivered but hardly unreasonable. They banned the RMTer and verified others were not affected. They promised to fully reimburse but warned it would take a month, so offered a 50% compromise if they just wanted money now. They nuked the thread because it technically broke forum rules but posted acknowledgement.
Like, yeah, it shouldn't take a month to math what the next highest bids were and reimburse the difference, I get that. Still, can't help but not give much shit about these p2w whales demanding that devs accept their indesputable evidence. Lazy game staff or not, it looked like a lot of entitled bratty whining to me.