aiyah.. like that quite difficult also... try bring to those 3rd party technician lo.. cos if u bring to apple, they will ask u to contact the person who sell it to you.

My place here, someone brought to apply service centre and the technician rejected it on the spot as he said it might be a stolen unit. He even suggested the customer to lodge a police report if the person who sell it to him is not contactable... LoL... I was there to send my MBP for service, and see all sorts of customer going to claim or request for service..