How to respond to ghosting

When it’s undebatable, straight up consistent ignoring your text messages – how does one navigate this?

I know one approach is to ghost the ghost, but what if it’s someone you need to work with in a team and they are consistently not responding to your messages on repeated occasions? I feel like it’s super disrespectful, especially when the texts involve planning events and carving out time. How does one interact with a ghost that they need to work together with? Calling them out seems inappropriate since this is likely to lead to defensiveness and ‘your emergency is not my priority’ type of responses from the ghost.

Any tips? Please send help