There should have been two codes included with your game, the Limted Edition online pass and the Premium code. After you redeem your Premium code and online pass and allowed both files to download to the HDD (a common mistake is to redeem the code but accidentally cancel the file's download to the HDD) make sure that you restart BF3 and upon restarting at the main title screen you will receive a pop up stating you are now premium and you will have a Premium background. From the main title screen go to the BF3 in game store and download the DLC expansions covered by Premium via the Premium tab of the BF3 in game store then close and restart BF3.
After the expansions download go to the games portion of the XMB and click on each expansion's bubble to install the game. After each expansion has been fully downloaded and installed restart BF3. At this point you will receive a series of pop ups stating that you now have each expansion. Now from the main menu go to multiplayer, open server browser and then open the server browser filter by clicking R3 and check all new maps and game modes or you won't find any games on the new expansions.
If you have redeemed both your online pass and premium code and you are still being asked to pay for the expansion packs try re-downloading both files from your download history in the PSN store making sure that they download to your HDD, then start BF3 and try the instructions above again. If it still tries to charge you then I recommend to contact a Game Advisor here: https://help.ea.com/contact-us
