You can always refute it. Whether you'll get your money back or not is an entirely different matter. The consumer protections on ACH are much weaker than credit cards, so it's pretty much up to the discretion of your bank.
It's not that their that much weaker. You have 60 days as an individual to dispute a debit, but it's seriously painful. You will likely have to go into a branch and fill out a physical document. In comparison, Amex has a link that says "dispute" next to each transaction.