People have very different ideas about how much has to be in a thing for it to be a whole story, or complete, or whatever. Looking at it purely from a perspective of: Is this a piece that will stand on its own as a WL page, where people will read it and say "this was a whole and entire story that I have now read"? I don't think it's enough for that.
It doesn't feel like a thing where there's an obvious place to expand it though, so I wouldn't necessarily say that you should just add two thousand words or something, rather I'd advise you not to rush into sharing it as a standalone thing. It could do well as tangent in something else, and since the actual milk part of the whole thing isn't really that integral to the story, you could replace it with just about anything that gets sold by people that ring somewhere to sell something, so you should be able to relatively easily adapt it for use as a tangent or anecdote or background to a character in a larger story.
Not that I'm saying you should now write a larger story to accommodate it, just that maybe you shouldn't push it out on its own just to be sad when it doesn't stick. There's no shame nor any cost to just putting it on a pile of thingies in your sandbox until a thing comes along where you can use it, or until the heat death of the universe makes the point moot.
I.e., it's not bad, but it isn't much either.
