Bella's reaction to the reveal was what surprised me the most. I really think she's the blackmailer, but after seeing her reaction to the reveal and Vanessa's hate, I think in her twisted mind, she believed she was just giving the MC s**t like she always does and was never actually going to reveal the secret. She honestly seemed to sympathize with the MC and was upset at Vanessa's reaction, which I didn't really expect.
EDIT - Oh yeah, and that see you next Tuesday selfie stick bitch needs Cleo to stomp on her ass. Hard.