"I'm deeply saddened to share with all the #SaltnPepa and #Spinderella fans that I will not be performing on the #NKOTB Mixtape Tour," she wrote.
"Despite my participation in promoting the tour and being highly publicized as one of the acts, in January 2019 I received a 'termination' email from #SaltnPepa excluding me from performances with the group."
"It was my expectation, after making that decision, that they would also take responsibility for sharing the news with the public and other affected parties. It has been months now with no mention."
She continued: "Out of love for my fans and a commitment to upholding a standard of professionalism, I've taken it upon myself to let everyone know. I refuse to participate in misleading fans, ticketholders, and others who -- based on all the advertising -- were anticipating seeing the iconic #SaltnPepa and #Spinderella trio.
"So, I'm making it clear now. Please know you will have the opportunity to see me this summer in many other projects and activities I'll be participating in and I look forward to seeing you all then. Thank you."
A rep for Salt-N-Pepa told TooFab they were "aware" of the post, but made no further comment.
The trio were just one of the 90s megastars billed to join New Kids On The Block on their new tour, which kicked off in Cincinnati on Thursday, along with Tiffany, Naughty By Nature and Debbie Gibson.
Indeed at the inaugural KAABOO Caymen in February, DJ Spinderella was billed to play with Salt-N-Pepa, but announced the day of she would not be performing "because of unresolved business that's preventing me from taking the stage"; the remaining twosome never even mentioned her absence during their set.
A new reality show called Ladies' Night starring all three — along with fellow 90s R&B trio SWV — just kicked off on BET.
Spinderella confirmed to TooFab through a rep that her "story will play out" on the upcoming episodes.
"There will be many more opportunities throughout the summer for fans to meet, greet, and rock with me, and I'm looking forward to sharing more news about that soon," she told us.
The show documents Salt-N-Pepa's journey to bring Las Vegas's first hip-hop residency — I Love The 90s — to the Paris Theatre. It opened last October, but lasted just six weeks. Spenderalla was dumped shortly afterward, suggesting the fallout stemmed from the Vegas failure.
In the first episode which broadcast on Tuesday, Pepa noted the reason for Spin's absence from their venue walkthrough was due to it being a "business meeting".
A rep for BET confirmed to TooFab on Friday DJ Spinderella will appear in every episode.
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Salt (Cheryl James) and Pepa (Sandra Denton) formed the eponymous group in 1985 with Latoya Hanson, but replaced her with Spinderella two years later.
The Grammy-winners, whose hit songs include "Push It", "Let's Talk About Sex" and "Whatta Man", have sold more than 15million records worldwide, and are among the top-selling female rap acts of all time.
Their hit "Shoop" meanwhile made a recent resurgence via the Deadpool soundtrack.
After posting on Thursday night, Spinderella received messages of support from her fellow DJs on Instagram, including DJ Jazzy Jeff, DJ Hurricane and Kid Capri, as well as rapper Yo-Yo and SWV's Taj George.
"We love you and you are forever implanted in this culture, get ready for your next phase..." Capri wrote.
Hurricane added: "I always believed that when one door close another opens. #newchapterbegins"