The singer and actress, 21, was in a polyamorous relationship with Internet and reality star Mongeau and rapper Mod Sun, 32, for nearly a year, before Thorne broke it off last February. Mongeau has since gotten engaged to fellow controversial Internet personality Jake Paul, which apparently isn't sitting well with her ex-lover.
Thorne took to Twitter on Wednesday, calling out her ex, writing, "Tana and I are no longer good. She broke girl code I’m over it."
Mongeau was quick to respond to Thorne, expressing her confusion at her former lover's disgust. "????? imagine taking every time ur mad at me to twitter but then telling ppl how much u care about me.................... wtf is this b :/," she tweeted.
Things continued to get ugly between the two, with Thorne firing back, "U legit started dating me for twitter.. how about u answer ur phone and talk to me instead of being on Twitter."
Mongeau replied minutes later, appearing to be hurt by Thorne's repeated attacks. "dude what are you doing bella? like i have no idea why you’re mad," she replied. "i’ve been texting you every minute since you tweeted, and for you to be tweeting me something as hurtful as saying I dated you for Twitter is literally f---ing nuts & if you honestly think that damn i lost you."
The pair's public argument seemed to subside after that, although it's unclear whether Thorne and Mongeau have decided to make peace.
This isn't the first time Thorne has publicly expressed her strained attitude towards Mongeau on social media. Several weeks ago, Thorne posted an Instagram photo showcasing her reaction to Mongeau's engagement to Jake Paul, writing, "When your ex gets engaged," along with over a dozen crying emojis.
Mongeau's recent activities have been documented in her new MTV reality program, "Tana Turns 21," which premiered earlier this month, and gives insight into her relationship with Paul, who has received his fair share of controversy over the last few years.