I love a good catfight!

Mariah Not Good Enough For Justin?
According to Kyle & Jackie O, hosts of the Countdown – Australia’s most popular and influential radio program, Justin Timberlake “doesn’t want to be associated” with Mariah, and that is why he personally will not allow the release of “Yours”. Not only that, but he said that Mariah is “uncool” and she “desperately” wants the duet released to regain her lost popularity.”
Which means that she turned him down for something other than music.