State tax filing

Today, I received a "Missing Documentation" letter from the Department of Taxation of VA. They requested copy of the tax that I paid to KY and am getting credit for it. I am not sure how to proceed. I used TurboTax and I can see that the requested document was at the bottom of my VA tax return filing, but after I called them they refused to help! The files that I have and I can send do not have a signature at the bottom as they were filed electronically. Would you advise how I may proceed?