As someone who has handled complaints in the past, someone saying "I'll never use you again" is just a ticket to whoever is dealing with you to say "fine, don't". People who handle complaints are there to recover goodwill. If you explicitly state there's none left and you won't use them again then...




However, the "opening two windows" phenomenon online is well known only by those people who get caught out by it, and by those who work in the industry. It's an easy mistake to make. I would be hopeful that a property could rectify this but getting what you want is all down to a tactful approach. Hopefully they will reconsider.