Rapper Iggy Azalea is known for her bruising battles on social media and Monday was unleashing her anger against a new enemy -- a pizza chain.

The Australian rapper, who was nominated in two top categories at the Grammy Awards in Los Angeles, apparently dined beforehand on a pizza -- simple cheese -- ordered from US chain Papa John's.

Several hours before Sunday's awards, Azalea unleashed the first of a volley of Twitter messages charging that the pizza deliverer had handed out her phone number.

The rapper accused Papa John's of violating her privacy, and attached pictures of unsolicited text messages from an apparent fan asking to see her.

The pizza chain, in an effort at humor that has become common for US corporations on social media, replied to Azalea that it "should have known better" and valued customer privacy and then quoted one of her songs: "Please don't bounce us!"

Azalea was not amused and by Monday had threatened legal action.

"When an employee steals information it's called data breach. It's illegal. There are steps a corporation is supposed to follow afterward," she tweeted.

"They don't include tweeting out song lyrics to the customer making the complaint," she said. "It's really unprofessional. I want a real answer."

Azalea has entered a series of high-profile testy exchanges on Twitter, most notably with rapper Azealia Banks who has accused the white Australian of exploitation by performing in a noticeably African American accent.

Amid the controversy over her nominations, Azalea came home empty-handed from the Grammys.