This guy was stealing my blinds for a couple of orbits. I decided to take a stand. Was it correct and did I play it correctly postflop?

Villain called all my flop and turn bets instantly. Do you think he was simply bluffing me, waiting for the check to bet strongly with ATC?

PokerStars - $0.02 NL - Holdem - 9 players
Hand converted by PokerTracker 4

CO: 48 BB (VPIP: 12.50, PFR: 12.50, 3Bet Preflop: 12.50, Hands: 25)
BTN: 94.5 BB (VPIP: 28.00, PFR: 20.00, 3Bet Preflop: 25.00, Hands: 25)
SB: 100 BB (VPIP: 13.51, PFR: 9.17, 3Bet Preflop: 3.92, Hands: 111)
Hero (BB): 103.5 BB
UTG: 121 BB (VPIP: 14.49, PFR: 10.87, 3Bet Preflop: 6.67, Hands: 138)
UTG+1: 82.5 BB (VPIP: 28.00, PFR: 12.00, 3Bet Preflop: 0.00, Hands: 25)
MP: 218.5 BB (VPIP: 20.16, PFR: 16.94, 3Bet Preflop: 5.41, Hands: 126)
MP+1: 94 BB (VPIP: 9.59, PFR: 6.51, 3Bet Preflop: 1.14, Hands: 296)
MP+2: 101.5 BB (VPIP: 14.02, PFR: 10.37, 3Bet Preflop: 8.33, Hands: 164)

SB posts SB 0.5 BB, Hero posts BB 1 BB

Pre Flop: (pot: 1.5 BB) Hero has K 6

fold, fold, fold, fold, fold, fold, BTN raises to 2.5 BB, fold, Hero raises to 7.5 BB, BTN calls 5 BB

Flop: (15.5 BB, 2 players) 4 7 7
Hero bets 7 BB, BTN calls 7 BB

Turn: (29.5 BB, 2 players) Q
Hero bets 19 BB, BTN calls 19 BB

River: (67.5 BB, 2 players) 3
Hero checks, BTN bets 48 BB, fold

BTN wins 65 BB

Fold preflop

don't 3b crap oop

nobody ever has ATC
you narrowed his range when you 3b pre
then flop
then turn by a lot

by the river, he's betting a straight, trips and sometimes a good Q
rest of his range is pairs and the occasional AhXh and KhXh

But how to defend my blinds? He was systematically raising and trying to steal every blinds. Shouldn't K6o be better than his range?

if the guy is opening way too much, you can consider calling K6o
it's not amazing and the rake at 2nl is going to make it very hard for you to make money, but it's a lot better than 3b a bad offsuit hand

to defend vs this guy, you 3b wider for value, ATo+,KJo+,55+,K9s+,QTs+
and call with your playable but not value hands

You said a couple orbits. A couple orbits is nothing. Call with suited hands and big hands. Offsuit trash just gets you into trouble.