That doesn't sound like something Great Gulf would do. They are always on top of things.
It sounds like it could be an error on your letter. Maybe it was supposed to be Jan 23 instead of Jun 23.
I would call them up.
Daniels owes it to the purchasers and investors in this building to redo this art entrance... Daniels has screwed over the investors who bought in Cinema Tower on SO MANY levels... and fixing this entrance is the LEAST they could do.