The only two ways to get an EIN Verification Letter (147C) is to call the IRS at 1-800-829-4933, or to mail the IRS a written request. Print your EIN confirmation letter for your records.Who can use this tool. This confirmation letter is known as Form CP 575 and is mailed to the address mentioned in your Form SS-4 application. 1. Electronically - Go to our website at MyTax.illinois. If you apply online, you can download the EIN Confirmation Letter at the end. How to Contact the IRS for EIN Verification Letter? The IRS asks that you send a letter, on company letterhead (if available) providing the name and Social Security Number of the owner(s) of the LLC. Second St., 351 Howlett Building, Springfield, IL 62756, 217-524-8008. The name may be available if a "no records found" result appears.