I also suspect it's unlikely we'll hear again from the OP, but in case there is further communication, it sounds as if the free night at issue was the one that could be earned late in 2020 through a "stay twice, earn one" promotion. Unlike the CC free nights that were extended, IHG has never indicated that these certs could be extended. I earned one late last year through this promotion, and it had a firm end date of May 31, 2021. I used it just last week to avoid any issues.

The T&Cs clearly cover this situation. Just like the CC cert, there was a 40K limit on the hotels where this earned cert could be used. Thus, customer service was NEVER going to offer 50,000 points in recompense for a loss of a 40K cert.

And OP, if you come back, each CSR (and supervisor) generally has a script they must follow and limitations in their discretion. I suspect when you get to the supervisory level with a claim such as this where the T&Cs clearly govern and there's little IHG expects to do, a supervisor may be allowed to offer 5K to a caller that won't get off the phone in order to turn over the phone so that they could move on to another caller. You've heard that message before a CSR call starts--"this call may be recorded for quality control purposes"? Not only are the contents of the call monitored, the lengths are monitored as well so while a frontline CSR may have no discretion, a supervisor who sees that a persistent caller won't end the call may be allowed to offer 5K points in a last-ditch effort to close the call. If that doesn't work, I'm sure the supervisor moves to end the call without making any further offers.