I think Ive got the same problem. When I clicked Send Game Request and switched back to the game i still have the credits.
Btw, sometimes when i swithed back to the game i get a blue screen with wierd characters.
lol. mta site and forums arent blocked in my school. All those big game site like gamespy.com are blocked, but I just used the ip to get me there and hopefully when this community grows bigger it wont get blocked from school.