Photo source
Why? Well she tweeted that it's to work on her album.
“Barbz I'm sorry 2 say I will not be going out on RiRi's tour. I've decided 2 use that time 4 the completion of my album. Hope u understand.
Not sure about that, I would not let an opportunity like that go. It's where you test your skills, where you connect with fans, and a sure way to get paid. Good luck with the album my girl.