Can't activate game [ Edited ]

[KryptonElement0]

This issue happened over a few months ago but I'm deciding to post it now as it's unsolved as of today. This is similar to the BF3 problem, just throwing that out there. After I put in the DS3 disk into my pc I booted up origin and typed in the activation code through origin itself, instead of installing then activating it. After installing it I'm prompted with a message saying 'We could not activated Dead Space 3 on this computer using the Origin account provided. Enter the key again yadayadayada." Clicking Enter Product Key does nothing, until I click 'Sign in as another User' and sign into my account AGAIN. Then I enter the activation code which i used in the beginning (the only code I have, to make that clear) and it says 'Key already used'. Why can't it detect that I already activated it? Any help?

EDIT: I'm using the Limited Editon and I bought it from Gamestop

[EA_Barry]

Please make contact with an EA Game Advisor for assistance. Click the following link to get started: http://help.ea.com/en/contact-us/new/?category=demo-beta

For help on how to contact an Advisor please use this link: http://answers.ea.com/t5/EA-Help-Beta/How-to-contact-a-Game-Advisor-using-the-new-EA-Help-page/td-p/...