Angel Exford shopped her ex to the police after finding out he stole her money to take his new girlfriend to Paris.
The 29-year-old's friends went to the airport with the police to confront Michael Fehsenfeld, 26, just before he was due to fly.
He was arrested and in October was convicted of fraud - but Angel's ordeal hasn't ended there.
Fehsenfeld, from Milton Keynes, has gone on to brag about his crimes and has even recorded a song called #FraudBae.
The video for the song was uploaded onto YouTube on Sunday and has since racked up 62,000 views.
Angel tells Radio 1 Newsbeat: "I wasn't surprised he did this. He's quite a brazen guy. It didn't bother me at all.
"I feel like he's mocking the whole situation. He's committed a crime. He's a thief and he's basically glamorising crime which I don't think is cute at all.
"I don't condone this music video at all. At the same time he's trying to save face, he's trying to salvage the situation.
"This is a coping mechanism for him I think."
Angel dated Fehsenfeld for around two months and during a night out he claimed he'd lost his wallet so he borrowed her card to pay for their drinks.
She says he promised to pay her back but didn't get in touch and the pair stopped talking.
A couple of weeks later she noticed random transactions on her bank statements.
"It turns out he's the guy that was using my card. He paid for a trip to Paris, hotel, he paid his Sky bill," she says.
"He even sent his girlfriend flowers from my card to her workplace."
I went on his gf’s insta highlights to see if I can get more evidence, you’d never guess what I found, a bouquet of flowers he sent her recently, from ...drum roll... yup you got it “Prestige Flowers”. Which also matches the timeline of my bank statement. *zoom in for surprise* pic.twitter.com/IlI2R7b1yD— NeeCee ✨ (@blessed_angell) October 31, 2018
Angel made a group chat with her friends titled #fraudbae where they gathered all the evidence.
She reported it to the police and officers went to the airport where he was arrested.
Michael Fehsenfeld, from Westcroft, Milton Keynes, was sentenced to 26 weeks in prison suspended for two years and 150 hours community service.
"We rejoiced and we were so happy," Angel says. "We were planning to have an awards ceremony for the girls and a sleepover.
"But then a couple of days later before he had to go to court to get sentenced he started posting these captions like 'Oh you think you've caught me red-handed'.
"He was being so smug. I thought I needed people to know."
Angel decided to expose him on social media by telling her followers exactly what happened.
**Part 1**— NeeCee ✨ (@blessed_angell) October 31, 2018
Aight, Boom, so this is a thread about how @michael_modern stole my bank details and spent over £1200 of MY money to impress HIS girlfriend, including receipts.
Story time ☕️ sit tight. I have time today. pic.twitter.com/HdrisWOWML
Since the story went viral, Angel has had people accusing her of making it up and saying she's working with Michael for publicity.
"Because the story sounds so surreal that's why people don't believe it - I don't believe it either and I'm in it," she says
"Till today I'm still in denial about it. When I tell people they're like 'Nah' and I'm like 'I know'.
"The evidence is all there."
I stopped explaining myself when I realised people only understand from their level of perception 📝 pic.twitter.com/kJOAbGSkzJ— NeeCee ✨ (@blessed_angell) November 11, 2018
Angel says she initially regretted exposing her ex but she didn't expect for him to release a song.
She says he's brought his actions back up and she no longer has sympathy for him.
"Reality is going to hit him sooner or later.
"At the end of the day everyone else is going to have to go to work and everyone is going to get on with their lives and he's going to be in the same position.
"He's going to be stuck in this negative light."
Angel says she hopes people will remember that what he did is a crime and in the future she wants to be part of fraud awareness.
"People are inboxing me telling me stories and this has inspired me to really work on a project that's going to raise awareness of fraud.
"To help women who are in the same situation as I am who haven't had the voice to stand up."