Siege of Centauri key can't be activated
After receiving my beta key for Siege of Centauri earlier today I have encountered an issue attempting to activate the code on Steam. When I attempt to activate the key, steam rejects the key and reports that the product code has already been activated by a different Steam account. I verified that the code is the same in the email and under "My Downloads" under my account.
Any help that can be provided with this would be appreciated.