I'd have to say, you have a serious decision to make. The company has just signaled that you will NEVER move up from where you are. If you're OK with that, fine, but remember, in that situation, you are also a replaceable asset

I'd be totally professional, train my replacement as well as I could (while taking careful note), and have my resume out on the street. When it came to to give notice, and they asked why, I would remind them of the passed over promotion, and the fact that it was a clear notice that my options were limited at the company from that day forward. I'd wish them well, and leave

BTW when/if they ended up calling with any "non trivial" questions, you say "You may hire SARbound consulting, my current going rate is (say $125/hr), with a 4 hour minimum if I have to come in, or billed by the 1/10th hour on the phone, from the time the phone rings, till the time I hang up, rounded up to the nearest 10th" - aka act like a professional - a lawyer