My DH and I rec'd a letter in the mail yrs ago from the IRS about our return. It did come registered. They had the nerve to ask for our phone number. I kept sending them what they wanted by mail until I got tired of it,then I called them. I wouldn't give them my number because at the time we both worked 11 to 7,and if they had called us I probably would have agreed that we owed them money.