"You have created too many publications: 422090725"

Hey, looking for support here as there's none on the Substack website.

I got a little enthusiastic while trying to settle on my publication name and created several, thinking I would delete them later once I decided on the right one.

Well, I got the error message above, then went and deleted several of the publications thinking I had just reached the limit. But, even after deleting many, I'm still getting the error.

How can I reset this?