Since, as you say, the dates keep changing, it seems obvious that their estimate is
not accurate, nor should it be relied upon...so why are you checking a couple of times a day? You've already proven their estimate is a meaningless guess. There are far too many variables in a "
just in time inventory" world to give a reliable time frame.
Until you get a VIN assigned, it'll only be a wild guess akin to asking the host at a busy restaurant when a table will be free (they're told to say "
5-10 minutes" every time you ask
)