You can try.... but there aren't too many IRS folks answering the phones.

You *might* have better luck with the practioner hotline; but even that line is difficult to get thru on.

You can inquire about or cancel an IRS Electronic Funds Withdrawal using the phone number found in the last paragraph here....if I remember correctly, its all automated, you dont have to wait for a human.

https://www.irs.gov/payments/pay-taxes-by-electronic-funds-withdrawal

Even one schedule via the software/efile?   That's good news if so.

Yes, Electronic Funds Withdrawal through the software.  Both balance due and estimated payments.

FYI Lacerte prints the Treasury phone number on the Letter
To cancel the payment, call the U.S. Treasury Financial Agent at 1-888-353-4537 no later than 2 business days prior to the payment (settlement) date. 

Ha !.... who knew?!?  Since I never set any of my clients up for those direct payments ( I don't want the responsibility) I did not know that.  Guess this old dog CAN learn something new.  Thanks.