Did you claim the item from the Cartel Market? (If not, go back on the same character and do it.)
Did you then right-click to use the item in your inventory? (See above.)
These may sound like basic questions, but we've had a series of people over the years who didn't know that it was necessary to do those things, and who expected that these unlocks would work like they work in other games, where you hand over the equivalent of CCs and the unlock is applied immediately.