I suggest that you enable call logs to be retrieved indefinitely into the past as I believe many users are like us - businesses who don't usually need to retrieve call logs except under unusual circumstances (like in our case, an IRS audit!).
I need our call logs for January - December 2020 in order to respond to an IRS audit. We have never needed to retrieve our call logs in the past so we did not set up Archiver, and I was not aware of the time limitation on call log retrieval. I contacted Support by phone and chat and they both told me that those call logs are irretrievable, which I frankly find hard to believe in this day and age.
You have the data, and the cost of storing the data nowadays is negligible, so I suggest that you keep the data and make it available to your customers. This wouldn't be as much of an issue if you "pushed" the data through every month to your customers, or sent it in a paper bill every month like the POTS companies do, but since you make it an optional AND UNOBVIOUS time-limited "pull" task, I think you owe it to your customers to give them access to data on their own usage.
In the Middle Ages parchment was expensive and not easily available, so scholars and monks would often erase previous manuscripts to be able to write another (https://en.wikipedia.org/wiki/Palimpsest). I hope that RingCentral is past that stage now.