seriously, blame yourself. When I saw the name Tan Boon Hui in your post , I am speechless not sure whether to laugh or to pity you. Don't believe me, try to search his case in this forum.

Secondly, you will have to bear the losses as you are the one dealing with the buyer. I assume you as a middleman in this case. Whatever happen between you and buyer is between both of you, and whatever happens between you and your dealer(the one that provide you with the fund) is your problem. Don't blame the problem to the dealer esp. when your buyer deal with you and not your dealer.

Thirdly, as said earlier, you can ask PayPal Singapore to check it for you. If the paypal are reversed to your account or to your dealer account after that, you can ask back from your dealer assuming if the paypal is reversed to the origin account or back to your own account.

Fourthly, why risking yourself with so much money involved? I assume you are still a student based from your post. You know, trading paypal have higher risk chances of being conned apart from handphones. If you don't have much capital to back you up in case of anything unwanted happens(in this case, reversal), why still take the risk? The profit might be nice, but the risk you are dealing unknown to you is much higher esp. when you deal with someone that you've never meet/seen and trusting blindly through virtually.