Agree with the poster who pointed out that they've picked up on you not wanting to give punishments.
Knickers to that. Give punishments. Dish out as many consequences as you have to to make it clear that what you say goes. You're in charge, and they need to feel it.
I'm teaching kids who are a year younger than yours (if the year system matches up, not sure as we are likely in different countries) and I had some similar problems with "you just hate me" or "you're picking on me, it's not fair" whenever I tried to call something out. So I just pulled on my "I don't care" pants and started throwing people out every time they defied me.
That said, a vague disclaimer is no one's friend, so I made it perfectly, painfully clear BEFORE I started throwing people out, what would happen if they defied me, so that they couldn't later say "that's not fair, I didn't know" lol. I told my class, they learn to sit still, listen, and not talk while the teacher is talking in their new entrant year, so if they can't manage it now, at the top of the school, that obviously means they need to go and spend some time with [NE teacher], with whom I have a prior arrangement.
It's nice if your kids like you, but it's far more important that they respect you. Having said that, I've found that having such clear boundaries hasn't necessarily turned my kids off. They seem to really enjoy me (based on, they seek me out for conversation, they wave to me in the playground, they invite me to join their games, they get excited at seeing me out in the real world, etc).