TV watchdog Ofcom received more than 300 complaints about this year's show from viewers.
Speaking in last week's Coming Out show, Iain insisted there was never any bullying as far as he was concerned.
He said on the show: "There was no bullying going on. Let's quash this rumour once and for all. Bullying is a very serious thing. It's a huge word. There was no bullying whatsoever."
However after watching the show back and seeing what he hadn't in camp, Iain suggested he had changed his mind.
Iain tweeted: "Bullying is a strong word. But I was unaware of a lot of what was said behind my back and also what some people said about me after they'd left."
Appearing today (Thursday) on ITV's Loose Women, Iain had his final say on the matter after speaking to the other celebs outside the jungle.
"I have spoken to Becky a lot on Whatsapp and Dennis too," Iain said. "The one that disappointed me the most was Amir, we got on really well and were going to go to Pakistan together.
"And then I saw some stuff afterwards where he was actually lying about me."
"I have no beef with any of them," Iain continued, insisting he didn't consider there to be any "bullying" in the camp.
"When I came out all these stories of bullying but I don't class it as bullying, it was people being slightly mean to me behind my back," he said.
"I was disappointed people had been saying things behind my back about having a game plan and not trying hard enough but when you're in there you do go nuts, you can have days of doing nothing."
In the Coming Out Show, Rebekah Vardy broke down in tears over the suggestion of bullying made by viewers.
She sobbed: "You know what, I was the one that was being the most supportive of him [Iain]… A bully? I've never been a bully in my whole entire life."
Dennis Wise later said: "Obviously Iain was in there to upset everything in the camp and that was his intention. If he's playing a game he's played it extremely well. He's obviously done it for his own reasons and that's up to Iain to explain himself."
I'm A Celebrity will return to ITV next year.