There is actually a way to delete Meetup groups, versus just leaving/stepping down from them. The Meetup docs are quite clear about the default behavior if you leave/step down: https://help.meetup.com/hc/en-us/articles/360002865332-Closi... The answer you needed was just a quick Google search away: https://www.google.com/search?q=delete+meetup+group , e.g. https://support.google.com/developergroups/answer/7378020?hl.…
At least the last time I used the site, the UI is actually not very clear about this, to the point where it seems almost intentional. (After all, it's to Meetup's advantage to have the group continue and collect money from someone else for it, rather than have it deleted by default).
There are actually a lot of problems with how Meetup handles organizers stepping down and/or billing. I've lost track of the number of groups I've been in that experienced a "hostile" takeover because (for example) the primary organizer's credit card expired, which created an opening for any member to become the primary organizer just by providing their credit card, even though the other organizers were still present.