Wrote to MR about the time I posted the original message and have heard nada.

Wrote to Chase a few days later. A few days after that we heard back from Chase:

"I have asked an Escalation Specialist to review your
request and contact you once the review has been
completed. You can expect a response from us by mail in
ten to fourteen business days. "

Because of a recent trip, we just got this letter today. Big nothing burger. Pointed out that 4 nights were posted to MR in January, said nothing at all about whether they had sent any nights in February, which was the question we asked. *Sigh!*

If no nights post tomorrow, then you can bet both MR and Chase will get more strongly worded follow ups.