In Underwood's post, the former pro football player wrote in part, "When our relationship ended we agreed to handle things as privately as possible as we attempted to navigate our new relationship as friends. I chose to do that since we were living in this interim period, but obviously a lot changed this week."
That specific comment seemed to be in reference to Randolph's interview on Monday's episode of The Bachelor: The Greatest Seasons -- Ever!, where she addressed their relationship and split, save any major details.
Randolph fired back at Underwood's post with one of her own, beginning by writing that she does "not wish to create an online petty war."
"Colton, as you know we made an agreement to not publicly discuss our break up. I have honored this, as have you thus far," she wrote on her Instagram Story. "As some of you may know, I did a GOAT interview this week -- I purposefully remained private and vague out of respect for Colton and our relationship."
"If you're wondering why I did the Bachelor GOAT interview, it's because I respect the fact that Bachelor brought me the platform that I have. I don't want to make enemies with, or turn my back on the franchise," Randolph continued. "I have no regrets, gained a great boyfriend and a healthy 1 1/2 year relationship, incredible and unique opportunities, and I platform that I intend to use for good. I want to show appreciation. I didn't see any harm in doing the interview, as I wasn't going to dish out details about our relationship to them."
Randolph went on to address Underwood's post specifically, writing that it "saddened" her and left her "frustrated."
"It seems you are subtly engaging in a tactic that peppers in aggressive comments such as 'that obviously changed this week' in order to make me look like the bad one," she wrote.
She then reiterated her desire for Underwood to "refrain from discussing our relationship," adding, "I would also like to ask that you don't cloud our great, 1 1/2 year relationship with a messy breakup."
Randolph then claimed that Underwood recently informed her that he'll be writing a new chapter of his memoir, The First Time.
"On Monday evening, you informed me you intend to monetize our breakup by writing a new chapter to discuss your experience with COVID (where you stayed in my family's house during your recovery and about our breakup)," she wrote. "You have also refused to give me any sort of approval on the chapter you will be writing, which will heavily feature me... This seems a bit unfair to me. Colton, you can do what you want, but please do not have a double standard."
Randolph concluded her post by asking Underwood to "refrain from prolonging our breakup, or dragging me, when we both know it's unwarranted."
"Neither of us, or anyone close to us, would have ever predicted that I would have to write this post," she wrote. "Again, I can't control your actions but I sincerely hope we can both move forward in peace. Thanking you in advance. I would prefer this to now be the end of this. I wish you nothing but the best & hope you can move on peacefully and successfully."
In a statement to E! News, a rep for Underwood said, "Her accusations are simply not true.
Watch the video below for more on the former couple.