called, said nothing and then hung up

I'm gotten a few calls from this phone number. It's not a phone number I recognize there for I'm not willing to waste my minutes on it.

I dont answer #'s i dont recognize, nor do i give Any info without 1st knowing whom im speaking with...
Some people get irrate, but you wouldn't allow anyone into your home without identifying themselves and their purpose 1st...
Rt!!??

Called several times never answers.