Dondunzak is a scammer.

Link to scammer's Sythe profile:http://sythe.org/member.php?u=228261
Briefly explain the trade:37m rsgp for 350k fifa ultimate team coins.
How they scammed: http://www.youtube.com/watch?v=uSZV7JwRzlE&feature=youtu.be
Proof that you were not talking to an impostor:here's a picture of me giving him my skype details that's in the video. http://tinypic.com/r/3149heg/6
Trade screenshots:http://tinypic.com/r/3149heg/6

 

You need to show his unique Skype Id, also, the video just seems to cut off as soon as you trade him, do you have a full video of the trade?

 

I cut it off because as you see, he blocks me on skype and loggs on runecape. So I turned it off.

 

Exchanged pm's, lacking proof.