Are you sure the letter is not a scam. Call the Iowa Department of Revenue if there are doubts. Search the web for its number. Do not use the number in the letter. If real, there are only two options. use a professional or do the return manually. Either option requires that the documents necessary to prepare the return are available. The IRS no longer maintains the federal copy of the return and Turbotax no longer maintains the xxxx.tax2015 file. If real this letter must not be ignored since it will take actions to collect the amount it deems due. For this reason, I think the best option would be to consult a professional.
