Hello All,
The song and video came out around 1998-1999.
The artist was a group consisting of 3 black women.
The video was a broken-hearted women contemplating suicide by jumping from a building (I think).
The song begins by the following lyric:
"When did you decide you were leaving?"
The lyrics' chorus contained:
"You did me wrong baby, it hurts me but hey, so long!"

It's a very smooth, song and the 95.5 Smooth Jazz station in Chicago played it all the time. Please help me find this song, thank you!

It was pretty easy to Google. I put the one line you had there in Google and it was the first thing that came up.

Lyrics: So Long (Well, Well, Well) by Phajja