Taxes were filed but not paid (did not debit my checking account)

I used TurboTax as usual this year and received the "Your taxes have been successfully filed!" message for my federal and two state income taxes. Three weekls later, I recieved a CP 60 notice from the IRS saying that I had not paid my taxes. I looked at my checking account and, sure enough, the checking account that I had provided to Turbo Tax had not been debited for any of the three,

What gives?