Sign inJoin freeFind your peopleSee the Spaces you belong to, and leave one from Settings.
When you join a Space, paid or free, it shows up on Settings → Memberships. That is the list of communities you belong to, not the Frequency Crew plan.
Plan and billing is still your Frequency plan (Crew). The two sit next to each other so a payment you make to a community is not mixed up with a payment you make to Frequency.