The Beef Between Game And G-Unit Crew

Can someone plz tell me what really started the beef btwn The Game and The G-Unit crew, because to me the Game and 5o cent are one great collab and i alwayz look forward to hear them do some rubbish together. And i heard in a concert that The Game threw the G-Uint Bling off his neck and threw it to the crowd. If its true, then what really caused the beef. Please i need to know.

50 made g unit