1st make sure you are logging into the correct account, the account for which the game/s were registered.
"invalid" means the code format is wrong. Should be 5 sets of 4 alphanumeric codes seperated by spaces, try without spacing. Can also happen if you're trying to redeem a box set game code on a digital code entry system (Origin site)
"used" means the code is already registered to an Origin account (digital download)
If you still have a problem, contact Customer Service/Game Advisors, here's how:
1 Click on the following link: https://help.ea.com/contact-us
2 Make sure you are logged in (top right corner)
3 Click on the blue button "Contact a Game Advisor"
4 Enter the name of your game or product (or "Origin" for account-related issues) and click "Find Solutions"
5 Select the type of issue and the platform you play on, and click on "Find Solutions".
6 Click on the blue button "I still need help" if the FAQ articles do not apply to your situation.
7 Select a contact option. Note that you may get different contact options depending on your country.