By the time you get this letter, you’ll be well aware that the IRS is looking seriously at your tax delinquency. The CP504 is the last warning you’ll get to pay up before the IRS takes further action.
Like the previous forms you’ve received, the CP504 will include your balance and any penalties and interest tacked on to your bill. It will also include a warning that if you fail to set up a payment plan or make other arrangements, the IRS has the legal ability to place liens or levies on your property.
If you feel your bill is incorrect, you can file an appeal with the IRS, but you must act before it is too late. This letter is your last chance to negotiate with the IRS before they begin taking more invasive measures.