Okay, this is just a suggestion, I don't know if it'll help (Don't have Premium for different reasons), but it's worth a shot.
Sign out of ALL things Battlefield. Battlelog, PSN, everything. Wait about an hour or so (Don't know how long to wait, but an hour should be more than long enough), then try logging back in on the Battlelog first. If it shows up that you have Premium, then try signing in and checking the in-game store for BF3. If there is still a price for them, and when clicking "Buy" or whatever the option is, it tries to charge you for the DLC you're downloading, post back and I'll see if I can help more.
Please see my post about this exact issue for the confirmed solution.
Linux Nation on PS: PlayStation Home Club President
Just tried this and no luck. In game store still trying to charge me, getting every feature but the expansions
You have to access/download the DLCs under the PSN you bought Premium under. I think you're not doing this.
We have 1 person that bought Premium here. And we have it for multiple users for 2 different PS3s. Only the person/PSN
who purchased the Premium has the option to actually see them listed on the game-disc's 'store' listed as free.
I didn't buy Premium, and when I tried to download the DLC map packs under my PSN, to our 2nd PS3, I was prompted
with the $14.99.
S E I J I N S H I . A L L D A Y . E V E R Y D A Y