(WA state) Hotel charged us an additional $800 per night after checkout

Location: Washington state

Throwaway because of identifying info on my main.

TLDR: My family and I recently stayed at a Seattle area hotel and were incorrectly charged an additional $800 a night, totaling around $3700, for four nights of our six night stay. This charge was originally for a second attached room that we did not receive upon check in due to a mistake during booking, and was later listed in the folio as an "upgrade charge" after we checked out. This is in addition to the listed nightly rate per room per night, which I received in an email from the hotel prior to check in. I am wondering if this violates the states Consumer Protection Act.

I have been trying to deal with this via the hotel before escalating as they refuse to refund this charge, and I was hoping for some clarification on if this violates state consumer rights laws and for advice on potential next steps.

The breakdown: I had originally booked a suite for August 2nd-8th that was two connecting rooms at this hotel, and decided to change the reservation to a larger suit they have that has an option to add a second connected room. I had looked up the rate for this suite and without the extra second bedroom it was similar to the original I had booked. I called July 7th to rebook into this room, requesting the additional second bedroom. I was told the second bedroom would be an additional $800 a night on top of the listed room rate, which I agreed to.

On July 31st I received an email from the hotel with the breakdown of the rate per room per night, which only included the suite, not the extra second room. This matched the original rate I had looked up just for the suite.

Upon checking in we were given only the suite, not the second attached room. When we spoke to a manager at the front desk he said a mistake was made in booking and unfortunately another family was staying in that room and they would be unable to give it to us. As we had plenty of room we got some rollaways for the kids and that was fine.

When I checked out I was told I had a zero balance and there was no folio to print. I asked to please have a printed copy of it and the response was "ZERO" and he then left the desk. Fortunately I have an account with the hotels parent company and was able to look up the folio there. Everything was correct except four nights had an $800 plus taxes "upgrade fee". When I called the hotel to ask about this I was told a mistake was made in booking and billing and a manager would get back to me. I received no follow up and continued to call, eventually reaching a manager at the front desk. He said he would look into it and email me later in the day.

When he emailed me he said the suite upgrade came with an $800 a night extra charge, on top of the listed room rate and as a gesture of goodwill said they would wave the two nights we were not charged it. All communication from then on was via email as I want a paper trail of this. I responded asking where this charge was disclosed as it was not listed as a part of the nightly rate on the room, and that I had been told the $800 was for a second bedroom we did not receive. I also asked if rebooking to a different room at their hotel came with additional hidden fees normally and for a link to where this was disclosed. All of his responses have avoided answering any questions I've asked and have instead been him repeating the same things.

At this point I want to escalate to either the hotel manager or their main office as this is an international luxury chain. I am curious though if this violates the states Consumer Protection Act and should be escalated to the Attorney General. A quick Google search shows similar issues from others who have stayed there in recent months, with the same response from the front desk when asked for a folio. Any legal advice would be appreciated.