Notice CP539 is a notification to you that the IRS is requiring all banks and financial institutions to withhold a portion of payments to you and send them to the IRS.
There could be several reasons why this has happened. Often, this is the first letter you have received about the issue and you didn't know a problem existed.
Usually, the trouble is because some bank or other financial entity does not have your Social Security or EIN or they have not entered it into their system correctly. You may simply have to contact them and complete a proper Form W-9. Read Pub 1281, which might be of assistance.
You do get credit for the tax payments on your next filed return, but the IRS keeps the money until then.
First, check to make sure all your banks have your Taxpayer Identifying Numbers correctly. Then call the IRS and determine exactly why this has happened.
If you can't get good answers, call Mr. Hopkins & we'll investigate!