I've lost 500 points, had 950, now I have 450.
Going to send a quick email off.
EDIT: I lost my points because it was on a points card I got free with the camera and they have expired
I bit crap but at least I know why they have gone.
As for where the 500 points are coming from, I read some people on other forums are saying that it's do with refunding the people who lost 500 points from ordereing GTA from Game but never used them.