I just did the same thing :( I mistakenly submitted a payment while e-filing my taxes.
I then checked my status the next day and it looked like the payment didn't go through so I arranged for the debit from my checking account again.
Yesterday, I saw two debits from my checking account by the IRS, for the same amount.
Bank had already moved the money, so I can't cancel it.
Some responses here have said that IRS will refund the money, once they see the duplicate.
Other responses say the IRS will keep it as an estimated payment for next year.
Does anyone know which answer is correct? Thank you!
