Use the sample letter on the next page if you want to tell the private collection agency to stop contacting you. How to use this sample letter: 1.You can find the CP or LTR number on the right corner of the letter. The IRS automatically provides filing and penalty relief to any taxpayer with an IRS address of record located in the disaster area. Available services may include the extension of tax return due dates, relief of penalty and interest, or replacement copies of records lost due to disasters. That said, you may be able to narrow it down. Have you recently interacted with the IRS or their site?