How to differentiate between "Dont you hang up" and "You dont hang up"?

then how to express "I don't want you not to hang up" in a formal way?

:) "Please dont end up our conversation in a rude way." I think thats a good way to express what I mean. Thank u for your attention and the terrific piece of advice.

"Somebody please have mercy,cause I just cant take it" It is a part of the lyrics of "Scream".What does it mean?