when aske who they were, the woman answered politley; NCO

This number calls cell phone all times starting early in the morning and doesn't stop until late at night.  When answered no one responds, or they hang up~I have got where I just try to ignore.  I owe no one any $$.

on your cell phone, you have the ability to keep 100 contact numbers.  Each of those numbers, friends, family, businesses, etc...you can assign a ring tone...one of many or just one for all.  You have to do it individually.  Then set your call in tone to none and vibrate to none.  Then, when one of these sleeze balls calls on a non friendly number...one that is not in your 100 contact numbers, your phone will not ring or vibrate.  It doesn't solve the problem of them calling, but it may give you satisfaction that they are completely wasting their time.  
Copy and paste this on as many of these sites as possible...

These NCO people are relentless.  They call my business line every couple of hours starting at 8:50 AM and go until about 8 pm.  Its the worst I have ever seen in terms of being persistant and constant.  They will give up eventually.

I am religious and do not answer my phone from sunset on friday to sunrise monday morning. all my family and friends know this. I have told this NCO about my religious practice about a thousand times but they still keep calling. I got no calls on Easter sunday so when they called the following week I asked them why and they said it was Easter. I asked them if there was only one religion in the USA. they said no. I told them that they need to respect all religious beliefs, especially after they have been told a thousand times. I think I will go to the CEO of the company and then to the press