See who's calling

I don't know who this is, but it is related to debt collection. They never leave a message, but ca incessantly starting at 8am. I'll receive at least 6 calls a day, 2 per hour in 10mim intervals...... , no voice-mails although I KNOW my voice-mail picks up. How can you trust a company that won't identify themselves! I pick up the calls every now and again and hear SILENCE...... whoever this is operates in a strange fashion. I hope more people speak out and companies stop using them, because I do