So grudgingly I offered the minimum bid, only to promptly receive a counter-bid almost 10 times as much.
Send a counter-offer $100 higher than your original one. You'd be surprised.
Also, I don't know about effectiveness of hiring a lawyer to fight a legal battle in South Korea, but you can actually hire an intermediary from (I suspect) the very same company that they are now parked with, which is also based in Germany and is well represented everywhere in Europe, name starts with an "S" :) . These guys take something like 10% + some more % for the transaction but they know how to bargain, so if your direct efforts fail, you can always hire an experienced broker.