As of now, there has been no charge on my credit card. I have not actually cancelled the reservation (again) as I was waiting to hear back from Marriott.
I did not screen shot the cancellation as I was not able to get to a screen with a cancellation number, I just got repeated "timed out" messages. Hence my original call to Marriott to cancel the reservation.
In retrospect, yes, I should have gotten cancellation numbers- but I was more concerned at the time that my Moana reservations seemed to have disappeared.
Often1, I don't have the agent number of who I spoke to-- When I asked for a way to identify the agent I spoke to today, all he would tell me was his first name (Prem)-- I asked him specifically how I could document that he was who I spoke to and he said he was only supposed to give a first name. I believe the name of the agent I spoke to on December 19 was Shen.