If he is, as you say, Chinese, you need to factor in the FACE factor: no Chinese having "not much money" would ever admit to that! Clearly a negotiating tactic
Dropping your price from $12,500 to $4,500 showed desperation to sell, your need for quick cash. No wonder the buyer is holding firm at 2,000.
If you're under the hammer and need the quick cash, put a clock on your last $4,500 offer, but not to short... say, 10 days or end of the month. Otherwise price goes up to $12,500 or more... me, I'd price it at $18,888 (Chinese love 8's, but they abhor 4's!)
Make sure to mention that you are interested in a quick sale (that much is obvious anyway) and are actively promoting this domain, that is to say, talking to other potential buyers and that the terms are first come first serve. Don't expect the buyer to cave in. Stay the course, stay quiet. Then 72 hours to deadline, remind him the price is going up on such and such date at 11:59 p.m. EST or GMT. Remind him once again 24 hours to deadline. Don't expect a reply.
Once past deadline, thank him for his interest and remind him the new price is $12,500 or whatever. Again, don't expect a reply. While there's a slim chance all this drama will elicit something, this is mainly to show your situation is not as desperate as you made it seem with your price drop to $4,500
In the meantime, make good on your word and... start talking to other potential buyers... I'd start with trademark lawyers and others specializing trademarking services (TM + GO)... if nothing else, this will boost your confidence in negotiations with the current interested party
Last but not least: believe it or not, when negotiating with Chinese, it's a good idea to talk/email them... in Chinese
Good luck!
Andrew