I need help dealing w/the IRS. I received a notice of deficiency in the mail. Can I use the validation techinique with them? I actually received the first letter the same day as my 341 hearing! They say I under-reported and now I owe them $900. I have not signed any agreements to set up payments. I just want them to prove that I made a mistake. I have moved and in the process lost my tax papers for that tax year(2000). Can anyone offer advice on dealing the Uncle Sam?