when did you indicate your credit card should be charged. it should have taken place on that date or maybe even a few days later. if its way after the date you specified then its likely you entered something incorrectly so the IRS could not charge you CC or maybe the charge would have put you over the card's limit and the CC company rejected the charge.
go to the IRS website and make payment now if it's way after date specified (or you could call IRS to see what the issue is) your payment is now late and you are subject to late payment penalties and interest which increase with every passing day.