How can I delete the PostgreSQL user in my mac? because, there is no user in the preference

I forgot how I install postgresql before.
and now I have removed it by following this steps https://stackoverflow.com/a/9240197/12381565 .

But my postgresql user didn't gone from the taskbar, although in my user preference is doesn't have it, so I can't remove it again in the preference.

Maybe I deleted it once, but I forgot about it. thank you.