Kandi Burruss and Tiny Cottle at Odds Over Xscape Reunion: 'Are You In or Are You Out?'

Xscape: Still Kickin' It kicks off takes fans inside the '90s R&B supergroup as they reunite, including the battles between Kandi Burruss and Tameka "Tiny" Cottle

Kandi Burruss, Tameka “Tiny” Cottle, and sisters LaTocha and Tamika Scott are pulling back the curtain on their highly anticipated Xscape reunion in a new four-part Bravo series — and PEOPLE’s got a first the first look at Sunday’s premiere.

Xscape: Still Kickin’ It kicks off takes fans inside the ’90s R&B supergroup as they find their new groove and prep for a performance at the 2017 Essence Festival, their first full live performance together in nearly 15 years.

It’s a welcomed return for the group, who burst onto the music scene in 1993 with their debut single, “Just Kickin’ It,” and album Hummin’ Comin’ at ‘Cha. The record would go on to be their first of three consecutive platinum albums — launching six top 10 singles, including R&B playlist staples like “Understanding,” “My Little Secret” and “Who Can I Run To.”

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But internal fighting and a lack of guidance eventually caused Xscape to part ways in the early 2000s. And as they talk about the idea of a reunion on their reality series, fans will see that not all of the ladies were immediately on board to get back.

“I’m not comfortable yet!” Burruss, 41, confesses in the clip — her frustration directed towards Cottle, 42, who appears to have signed Burruss up for the reunion with the Scott sisters prematurely. “I told her I do not want to engage in anything too deep with the girls unless I am comfortable.”

“You are frustrating me right now,” the Real Housewives of Atlanta star later yells at Cottle during a tense one-on-one. “Everything that we discussed, you are totally changing. I said I didn’t know how I feel about us joining our names on a company yet because I didn’t know how I feel about us definitely doing business yet. Don’t you think before y’all made a decision to come up with this company that y’all came up with that y’all just put my name on a company? Who just puts somebody’s name on a company?”

Cottle isn’t having it. “I’ve been said I want to do shows. I’ve told you that,” she shouts back. “Kandi, either you in or you out. What you want to do? Are you in or are you out?”

Xscape: Still Kickin’ It airs Sundays (at 9 p.m. ET) on Bravo.