The IRS uses Notice CP44 to tell you they are delaying your refund until it is determined whether you owe other taxes. Of course, if you do owe more taxes they will send you a letter like Notice CP49.
Response to Notice CP44
The way to find out if you owe other taxes is to call the IRS at 1-800-829-1040 & order your Account Transcripts. These are chronological reports for all entries in each year & they will tell you if any other problems exist.
From there, it's worthwhile to see if the tax can be lowered for any year. You have 2 years from the payment date to recover the taxes paid.
If you have any uncertainty, please follow the Prep Steps & contact this office!