"My (work) friend commented on his Instagram page so he stalked him on Facebook to find out where he worked."
The caller claimed that in an attempt to get put through to the person who left an abusive message on his Instagram, Nasser posed as the person's dad and said there had been a family emergency and he needed to speak to the person.
The call was never put through and Nasser didn't have private number on so when Rosie called the number back she realised it was the Married At First Sight star who was calling.
"He's lost the plot," a shocked Jackie O said.
Nasser then called through to the radio program and defended himself against the caller.
"You don't leave messages on my Instagram bagging me out and putting rubbish on me when you don't even know me," Nasser said to the caller, Rosie.
"I will ring up the haters and this is what the problem is with this country, why should we sit down and take it?" he continued.
KIIS FM's newsreader, Brooklyn Ross, suggested to Nasser that he make his Instagram account private if he doesn't want negative comments, but the reality contestant ignored the suggestion.
"Nasser, how many people are you calling a day because I do see a lot of people troll you on Instagram," Jackie O asked.
"Listen, there's a video coming out … where I do ring people and they apologise to me," Nasser said to the radio hosts.
"Let me tell you, guys, there is a 12-year-old girl and the message that she left to me was disgraceful … watch out for that video, I ring the school," he said.
"Nasser, you can't do that," an outraged Jackie O said. "You can't start abusing a 12-year-old!"
"Yes I can," Nasser replied. "She said, 'I hate your f'ing guts. Why don't you go away, you piece of s**t.' A 12-year-old doesn't say that on someone's Instagram so I rang the school in Canberra and I said to the principal, 'This is your student.' The principal goes, 'What? I can't believe it!'
"I'm not gonna take this," Nasser added.
Jackie O ended the break by once again saying, "I actually feel like Nasser is legit losing it!"