Why do I get a message Upgrade to a full account the next time I login to the game after I applied the free trial key to my own account from the invite a friend email that I sent to myself that already has the purchased game. Does it mean that I lost the full access to the game. My previous four digit code after the display name was 9710 but is overwritten with 5720 and the account now shows trial status with a message upgrade to a full account.
