The four Syrian men, who are all related to one another, said militants are flocking to leave the so-called ISIS amid heavy military losses.
After escaping six weeks ago, the men - two of whom are brothers - spoke to the Sunday Times about the shocking brutality under the regime.
Abu Omar, 25, said: "Life was miserable in the caliphate.
"The people were not happy, and many want to leave. They steal from people and kill their own fighters, sometimes for no reason.”
His cousin Mahmoud added: "When we first came there, they were fair and just. Now they’re not. We expected life to be better, but it wasn’t.”
Speaking from a hideout near Syria's border with Turkey, they told how foreign fighters, including women, appeared to revel in the sickening violence which became commonplace in Isis-controlled areas of Syria and Iraq.
Mr Omar said: "We saw one woman who had tried to escape being stoned to death.
“It was the foreign women who did it. Their husbands brought them. The women liked doing it because they thought it would bring them closer to God.”
The group said ISIS is now becoming even more ruthless in its violence after coming under pressure in recent weeks.
Mr Omar told the Sunday Times: "All the older fighters started to leave and they got desperate. That’s when they started recruiting Iraqi and Syrian children. They say it’s easy to convince young kids to blow themselves up.”
Lawyer Abu Shujah, who has helped around 100 European defectors, said there was a sharp rise in the number of people wanting to leave the so-called ISIS territory.
He added: "They’ve seen propaganda on the internet. When they arrive it’s different, but they can’t say anything against it.
"Most people leaving are French,” he said. “When they come to the consulate, most get passports and go back to France. They are kept for a few days for questioning, and then released. There are a lot of British people inside who want to defect, but their government doesn’t help them.”
Meanwhile, the four Syrian defectors say they now have nowhere to turn
Mr Omar said: "We don’t know where to go. We want to go further away, but Europe is too expensive.
“We know people are after us and want to kill us. We feel lost”, Abna reported.
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