Absolutely, ACH debits (and credits!) can fail. And due to the asynchronous nature of the ACH network, they can sometimes fail many days after their creation. Take a look at the 'Payment status' section of https://www.balancedpayments.com/ach-debits for some information.
Balanced provides webhooks/callbacks on transaction state updates, so users can always be made aware of the most current state of a transaction. The dashboard will also reflect the most current information, of course, as well as the API's response to a GET request.