Here is what happens to your Workspace when a card or bank debit fails.
First payment at checkout
If you pay by US bank account (ACH) and the first bank debit fails, your subscription is canceled and your Workspace stays on its current plan. A Workspace is never on Pro without paying. You can start again with the same account, a different bank account or a card.
Renewal or seat addition
Bank debit (ACH): your Workspace moves to Free and the unpaid invoice is voided. Tango doesn't retry bank debits, so nothing is left pending.
Card: a failed card charge is retried, and your subscription can be cancelled after the retry attempts.
Paying an invoice through its hosted invoice link
The card or bank account you use is saved for your future invoices.
How do I get back to Pro?
If your Workspace moved to Free after a failed bank debit, upgrade again from Settings & members > Billing.