Hello, I'll start off by stating that I have filed the 1040X amendment form after I did my taxes. I also payed the amount I owed for the 1040X form but I received a notice from the IRS telling me that I owe money. I lost the notice. So I'm trying to pay this online but I can't seem to figure out what form I'm paying for. Is it still the 1040X form or is it something completely different?