This is Sprints' third party verification service - they do not leave a message if you do not pick up - it's automated process to rate your recent customer service with Sprint.

They called today in the early evening, didn't leave a message. Unknown area code / other part of USA

These disgusting people keep calling me, and when I call it back I get the message "this number is not in service".  Hope they get herpes !

This is an Illinois area code.I got a call today. checked this thread, called it and I got a Sprint Cellular recorded message wanting me to complete a survey regarding a recent visit to a store and call to customer service, This may be a 3rd party service working for several companies. If your a Sprint customer and made contact recently with them this may be the case or due to a contact with another company.

Hope this helps

Got this call, didn't answer it.

I don't know who this is calling me and it's aggravating, can we make it stop?

Last two days been getting calls from this number.  I tried to call it back from another phone, but got a recorded message that "This number is not yet in service."

Still unsure who or what company this is from.

I dont know