Did you redeem a Bond for the FSW membership passcode?
If so, you have to pick up the code in the 'Messages' tab on your account.
Instructions on how to redeem the passcode are on the
Fresh Start Worlds
support page under the
"Fresh Start Worlds Membership Passcode"
heading.
If you redeemed a Bond for regular membership in-game and it hasn't worked, try logging fully out, closing down your window/app then opening up and logging back in.