(verb) (action): to take your partner's mobile (cell-phone) and change a few of the digits on their ex's phone number.
Example 1: Katrina - "Ha! He won't be able to send her a text any more, I did an ex-communicate while he was in the shower."
Tash - "Hey, Deb, I just got a call from James - he's wondering why you won't answer your messages or calls"
Deb - "I haven't got any from him, what's he talking about?"
Tash - "He says he's been trying to get in touch with you for weeks - he wants to apologise"
Deb - "Hahaha, that insecure bitch Katrina must have done an ex-communicate!"