A question about a simple hand

[krammatrix]

a simple hand, but i'm really not sure about a single decision i made in this hand. comment on preflop and postflop play please

Bodog $15 buy in tournament, 551 entrants, ~150 left
Blinds: 150/300
Hero has t3200 in chips, villain has t6000
Hero is in BB, villain in SB

Its folded around, and villain minraises to t600, hero picks up KJo and flat calls

Flop: AJ3 2 diamonds
Villain bets t300, hero calls t300

Turn: 7d
Villain bets t720, hero folds

I just feel like i did nothign to prevent him from just continuation betting his steal, should i have raised the flop? i lost 1/3 my chips on this hand, and i feel like i didn't do anything right. Advice would be greatly appreciated, thahnks