Issues with logging in ('Register code is already in use")

Hello, EA staff and fellow gamers. I bought Battlefield: Bad Company 2 last year and I've been having a lot of fun with it. Recently, though, I had to format my computer, so I reinstalled the game yesterday. When I tried to login into the multiplayer servers with my email and password, the first error I encountered was  that my 'account could not be found'. Since I typed my credentials correctly, I decided to restart the game and try again. After having no luck with it, I tried creating a new account. After supplying my serial key, I got a message that this register code is already in use. I went back to attempt another login, but now instead of the 'account not found' error, I was prompted with a License Agreement, and was asked to supply my key as if I was creating a new account. Of course, I got the same error message again ('Register code is already in use"). 

I tried the alternate route of login into Origin externally. That resulted in me updating my old EA account and using a new username -which I'm not sure how it will tie in with my BC2 account. I also tried retrieving my password, but no email arrives at all (I DID check the spam folder!).

I don't know what to do! I love the game but those issues are utterly frustrating. Any ideas?