The Hero singer was left embarrassed during her set on DICk Clark's New Year's Rockin' Eve on Saturday (31Dec16) when her in-ear monitors failed and she couldn't hear her backing track, so relied on the audience to sing her songs before cutting her performance short.
Since the show, there has been a war of words between her team, including manager Stella Bulochnikov, who placed the blame on the producers, and representatives for DICk Clark Productions.
Tommy, who helped launch Mariah's career in the 1990s and subsequently married her, has written a letter to the New York Post's gossip column Page Six in which he urges the singer to surround herself with a better team and also criticises their decision to do reality show Mariah's World.
“My only advice is that she should hire more seasoned and respected professionals to surround her and help her with her career!" he wrote. "I would never have encouraged her or guided her to do something like a reality television show!!!!! I don’t get it!! That does absolutely nothing for her integrity, her credibility, or her massive talent!!"
The 67-year-old, who was married to Mariah between 1993 and 1998, compares her current management team to the one she had at the start of her career, and is convinced she never had such problems back then.
"Most certainly none of these issues or problems ever existed with her in her early days at Sony for the first 10 years when she skyrocketed to global superstardom!!" he continued. "Where absolutely meticulous and methodical attention was paid to every single detail and nuance that went on into her career!”
He encourages her to take time to get perspective and figure out how to recover from the TV series and the New Year's blunder, which he said "could happen to anyone", although he suggests her technical people should have been paying more attention. He also defends her, telling the public to "back off and leave her the hell alone".
Stella responded to his letter by saying, “Really? Tommy is a relic. Did he give you that statement from a rotary phone?”
Mariah told Entertainment Weekly on Wednesday (04Jan17) she was "mortified" by the performance and she would be "less trusting of using anyone outside of my own team" in the future.