Rockstar has updated with advice regarding missing characters in GTA Online. Rockstar has advised anyone who has logged into GTA Online and found their missing character: To Not Create A New Character

Players who find an empty character slot need to return to story mode and then re-enter GTA Online through the pause menu, but only when the Rockstar Cloud Servers are working. Rockstar have also advised people who encounter a message stating that the servers are unavailable to keep on trying until they work. Rockstar have stressed to not continue online with saving disabled, as this may overwrite your character. 

“If you have previously created a character but see an empty character selection screen when entering GTA Online, please back out to GTAV Story Mode and try re-entering GTA Online through the pause menu (repeat or wait until Rockstar cloud servers are back up), Rockstar states on their support page. Do not create a new character in the empty slot where your character should be. 

“If you receive the message ‘The Rockstar Cloud Servers Are Unavailable’, please return to GTAV Story Mode and follow the steps above.  Please do not press ‘Retry’ on the message and do not proceed online with saving disabled, as this may lead to overwriting your existing character.”

Rockstar recently released a patch for both consoles which have helped remedy most of the launch issues.