I would.

But I would first contact the IRS and make sure that the notice originated from them. You can call the IRS at the following: 1-800-829-1040.

In addition to calling them, you can use the following website to determine what else you can do to expedite this matter. This website will explain the reasons why received the notice you received.

https://www.irs.gov/individuals/understanding-your-irs-notice-or-letter

The first thing I would do is call the IRS though, just to be safe.