The IRS uses Notice CP22A to inform you of changes to your return supposedly based on information you provided but often, you haven't provided them anything & this is your first notice. Be careful about what you say and send to the IRS. These will be held against you later!
The Notice CP22A is typically used for changes in filing status or dependency exemptions while Notice CP22I notifies you of changes to your IRA taxes. In addition to the Notice CP22, you will also receive a Publication 5219 which (barely) explains a Penalty Abatement Request.
Respond to Notice CP22
If you wish to contest this through the IRS administrative agency you have 60 days to file an Appeal. This is an inexpensive but a very slow process. (See Appeals Prep Steps) You also have the option of paying the amount & filing a claim for refund.
If your issue is simple, then an IRS Appeal would likely be best. But, if the issues are fact intensive or complicated, filing a claim for refund may be better because the US District Court or Court of Claims will have jurisdiction with inherent Equitable powers to protect you from the IRS.
But, it's obvious that the IRS has assessed the tax against you. Therefore, even if you dispute it, the IRS will want payment. So, please follow the Collection Prep Steps to get a payment agreement until the error on your file can be reversed.
Each issue is different so please follow the Prep Steps for IRS Notice CP22 and see Mr. Hopkins in Colorado Springs or Pueblo before proceeding!
But, after you respond, don't be surprised if the IRS sends you Letter 86C transferring your file to another office or Letter 2645 asking for more time! Then, you must follow up. Don't depend on the IRS!
Various IRS Notices CP22A: