I've been getting calls from this number almost every week and they don't leave a message. Why do companies continue to call me when I am on a do not call list and my number is unlisted?

Continuous calls to my phone from this number and they don't leave a message. When I call back, the number is  not in service, disconnected (even though I called back within 5 sec of receiving the call) What is going on in this country?

In response to your first post: Because one, they're scammers who ignore the DNC list and two, they're calling numbers at random so have no clue your number is unlisted.
In response to your second post: the number has been spoofed. Just block and ignore.