Move over, Naomi Campbell.

On Sunday's Kourtney and Khloe Take Miami, Kim Kardashian pays a visit to her sibs, but Kourtney gets irked because Kim, 29, is constantly on her phone.

"Kim is like a crack addict when it comes to her BlackBerry!" Kourtney, 31, complains in the clip (above). "If it's not in her hand, she literally starts twitching."

Kourtney ends up hiding Kim's phone -- and when Kim learns that she won't be getting a new one, she calls her sib the b-word and hurls Kourtney's phone at her.

The full episode of Kourtney and Khloe Take Miami airs Sunday at 10 p.m./ET on E!.