I just tried with big and little letters, and it still said it was invalid. All the letters and numbers are clear and don't have a double. I think I'm going to open Origin and hopefully talk to someone. It's crazy for it to still not be on my page, in a few days it will be a month since I got it!
EDIT: Well, I contacted them, and he gave me a new code, and I used it and it said it was registered but the icon is still grayed out. I told him and he said it has to do with a network issue, so I should try again later. Hopefully it's all sorted out and it'll be on my page later.