The simple fix for this is to add an option on the "Upgrade to Collector's Edition" for "I already have a code." and let you input it there, instead of having to pay another $20 for an automatic upgrade.

I honestly feel like the entire infrastructure for the game, including the account management, server techs and the people handling the backend are about 4 years old, and are communicating with each other and us in twinspeak.