As per the National Automated Clearing House Association (NACHA), there are only three allowable reasons to dispute an ACH Direct Debit charge as a customer:

• The transaction was never authorised or the authorisation was revoked.

• The transaction was processed on a date earlier than authorised (any date after is acceptable).

• The transaction is for an amount different than was authorised.
  

Unlike credit card disputes, all ACH Direct Debit disputes are final and there is no process to appeal. If a customer successfully disputes a payment, you must work with them directly to resolve the situation.

Additional information

• When a customer disputes an ACH Direct Debit payment, it invalidates the mandate associated with the payment method and you can't re-use it. To attempt charging again, you must resolve the dispute with the customer and collect a new mandate authorisation. If they dispute a subsequent payment, Stripe blocks the bank account from further use and you must contact Stripe support for further resolution.
• In rare situations, Stripe might receive an ACH failure from the bank after a payment has succeeded. If this happens, Stripe creates a dispute. You can read more about this in the documentation for ACH Direct Debits on the Charges API or PaymentIntents API.