When you ring a friend and leave a stupidly long message so that they have to listen to it all to delete it.
You can sing to them play an annoying song as long as it takes a lot of time and they hate the little voice mail icon.
Victim - "Oh look I have a voicemail"
Phone - *never gunna give you up*
5 Minutes later
Phone - *Who you gunna call Ghostbusters*
Victim - "I've been Fucking voice mail raped"
That would be voicemail rape