An error message says you cannot close your account because you have unpaid invoices.
If you are seeing an "unpaid invoices" message, one or more of the following is true:
- One or more of your Previous Invoices are unpaid (go to your Pay Balance page to pay)
- You have a "Pending" invoice that is scheduled to be charged soon
- You have a balance for the ongoing month that is scheduled to be billed next month
If you have any remaining ongoing charges, the Remove Credit Card feature will let you know what apps they're stemming from. Be sure downgrade your apps to Free Dynos and delete all add-ons (except the free Heroku Postgres). Alternately, you can just delete your apps. You can do any of this from your Heroku Dashboard or the CLI (as you prefer).
After successfully using the Remove Credit Card feature, you can proceed with closing your account.