After you file

There isn't an IRS office that handles credit card charges, that's why no number there.  It goes through an intermediary (the IRS doesn't accept credit cards directly).   There should be some way to contact that intermediary, though.  

I know if you choose ACH (which is the IRS directly processing) that nothing goes to the IRS if your return is rejected but it seems like with the credit cards something IS going somewhere.