you already suspected it to be fake. You should have done everything in your part to make sure it's not fake including asking the seller to confirm, checking stickers on the phone, checking the battery, checking the software and so on. before paying. Since you wanted convenience and trusted your friend to deal on behalf of you then sorry lah. Who is to blame?

You could either now take it as a lesson and accept refund of RM600 from Mr B or report to police. Cause if you don't mind a bit of inconvenience then report police and then report to nokia Malaysia. I think nokia malaysia should do something because their product is being duplicated. There are some legality to this.