Breaking up is hard to do. Rob Kardashian has called it quits with Rita Ora, but not before throwing her under the bus.

According The Sun, Rob Kardashian and Rita Ora had a secretive relationship that was kept out of the spotlight. Not any more. After a break up, Kardashian is now launching a full scale assault on Ora, and her reputation.

She cheated on me with nearly 20 dudes while we were together, I wonder how many she will sleep with now that we apart. But I mean 20?!

- Rob Kardashian

Kardashian posted that, and other scathing tweets twoard Ora, that have since been deleted. So far, no response from Rita Ora.

Unfortunately for Rita, the twitterverse is not on her side. Currently trending on Twitter: Rita Whora. Ouch.