I'd let her know she is loved, and supported, again. Then back way off, don't ask if and when she'll be around again. Just don't ask at all. Let her be the adult, give her a chance to miss you and by which she makes the plans. Do not change any of your plans going forward, don't buy extra food. When she finally comes around she can go pick up the food and maybe you have to still stick to the plans you made before she announced their arrival. Do not change your life at all for her. When she comes let her decide how it's spent and what you all do. Don't be the mom anymore, be the mom of a true adult. She feels the pressure of trying to be everything, to everybody. You are her safe place, have faith in her and her ability to know when she really needs you.
This is an adjustment, I know, I've had to do the same. You just need to remember that you raised a good girl and you've instilled a lot of lessons. One of the most important is independence. Let her fly.
In the mean time, find your girls and go out and have some fun. Have a margarita and vent to them about the brutality of motherhood. How hurt you are. Then when she calls because you haven't in awhile, and she will be confused, smile and ask her how she's doing....

This is a phase. Of course, if/when she has children you will see more of them when they want to go on holidays and stick you with the kids.(I am kid sitting three teenagers this weekend while their parents fly interstate for a wedding) Or indeed they may need a dog sitter while they take a cruise or something similar..(Been there, done that too)😷

Have you talked about it? That sounds like a face to face, but gently, she might have something going on. Do you know if her partner is a good person, because that's a definite possibility. Or she's exhausted from work...

I think a talk would be good. A big heart to heart. Even if it takes a few.

As someone who cut off a parent, I was very confused and a talk as equals could of made things very different.

The distance is odd for us in the states...esp. in the western US.

The distance you reference is a long weekend for us.

It about northern Idaho to Seattle, Washington. +/-

Can you visit them? Maybe schedule a hotel or bnb so as to signal you are not trying to impose.

If her partner IS sealing her off, that could be a red flag. Abusers like to isolate ...

How really sad, especially not answering when you call
I am really sorry for you

This is so typical. Our kids also tend to only text, not even email!

hope hes not abusing her,big hugs ruby🤗

I think you should go unannounced incase there is anything going on that shouldn't be. Either way you and your husband will know whats what.Good luck Ruby .