U. S. Grant Department Called to offer me $5000

I've been called three times in the last three weeks by a male with an Indian accent claiming to be from the "u. S. Grant Department."  The first time I was asleep and he left a message.  The second time he called he asked to speak to David, only he pronounced it "Dah-vid", with the first syllable rhyming with "cat."  I told him that my name is pronounced "Day-vid" in the U.S., and he got all upset and started calling me a liar, so I hung up on him.  Just now, 4 p.m. Pacific time, 1/15/2016, he called again and asked to speak to David.  I said, this is David, how can I help you?  He assumed I was a woman from the pitch of my voice and said, "David is a man's name, correct?"  I said "Yes, I'm a man and my name is David.  What do you want?"  Then he started on a spiel about the "U. S. Grant Department" wanting to give me $5000.  I told him, "There is no such department in the U.S. government," and hung up on him.  I assume he was phishing for bank account information.