My state tax return says $0 due, and the payment voucher says $2700 is due. Which is true?

[Carl]

More than likely you are confusing the estimated payment form with the voucher form. Are you looking at the 2018 form 1040-V? Or is it the 2019 form 1040-ES?

Another possibility is that if you also completed a state return, you may owe the state nothing, and the IRS $2700, or vice-versa. So check that.

On your federal return see line 22. If there's an amount on that line, that's what you owe the IRS.