Are you on 4.1 already? if it was me, I would restore and Jailbreak again. Its probably just a bug, my phone is jailbroken with limera1n and I still have facetime. If you used limera1n you can try greenpois0n, if you used gp try limera1n. If youre not on 4.1 though and you need your phone unlocked, don't restore, wait for a new ultrasn0w to come out.