TxTag.org False billing and made up account Dallas Texas

Recieved a bill from Txtag in the mail with my wifes name. TxTag operates toll roads in texas . The bill indicated 5 charges in the Austin area on may 14, 2016. The bill had an account number in my wife's name. There are several problems with all this. She never had an account with this organization, the license plate number on the bill returns to a 2013 Yamaha motorcycle, don't own one and never have. Oh, and last but not least my wife passed away in 2011. I called the number on the bill and spoke with a woman who had a real bad attitude. She would not give me any information because "  You are not your wife." Then demanded a death certificate and said if I did'nt pay there would be severe penalties. I told her I was'nt going to waste a stamp on them, and if they wanted to penalize my wife ( remember I'm not the account holder ) that she is in the Texas Veterans Cemetery in Abilene, and good luck talking to her, or anything else.