Complaint Review: US Federal Grant Department

 I have gotten multiple phone calls from different 202 area code numbers, all saying they are the US Federal Grant Dept. (202-765-6765, 202-407-6717, 202-660-4529) Every call has been from a foreign man with heavy accents and they are very rude.  The first couple calls I wouldn't let them say anything I'd just say I wasn't interested and please do not call me again.  I got responses saying, "We will just keep calling you there is nothing you can do," "I will call you 20 more times because I like your voice," and "I guess I will just put the grant money in my own account." Then I got another call and this time I let the guy talk and tell me about it, finally when he asked if I was interested I said I wasn't and to please not call again.  His response, "Why are you wasting my time?" So I said sir you were wasting my time, then he said "I will keep calling you and I am going to f**k you." I was shocked! I had to ask him what he had said because I didn't believe it at first. I told him I am going to report him to which he hung up.  I have since blocked all three of those numbers from my phone and hope to not get anymore calls from them but if they have 3 different numbers I am sure they have more.  I think from now on I will just swipe to answer and immediately hang up if it happens again and hopefully they will quit calling.