Admin-Hall

Adjective - to commit to something or someone, only to later go back on your word without any communication whatsoever. Especially in the context of a school, where the entire administrative hallway might have promised to do something, only to later go back on their word without any communication whatsoever.

He asked Macy to prom and then pulled an Admin-Hall on her and didn't show up.
They promised to help start a coffee shop and then pulled an Admin-Hall and didn't follow through.