The phone number is from OptumRx Prescription Service concerned with an order.
An automated phone system.
The best thing to do is to contact them at OptrumRx.com.
They have other phone numbers but not easy to reach a real person.

OPTUMRX prescription service.   Automatic messaging service.   If you use a cell phone, they revert voice mail.   Message normally concerned about filling your order.
Other phone numbers are:     800 788 4863    800 207 1581
May take time to speak to a live person.
Website:  Optumrx.com

This is Optum RX, a prescription drug company

Over the past two or three weeks, this unavailable number keeps appearing on our call id.  Our National Do Not Call system is certainly doing a poor job of monitoring this unwanted calls made to numbers that are on the Do Not Call list.

STOP THESE CALLS

Unwanted caller.  Calls twice a day.

Calls all day long.  Never leaves a message.  When we answer they never speak and it disconnects

FYI,
1)   Don't even pick up the call ----- you are not obligated to talk to anyone on unknown phone
numbers .    Surely you don't open unknown e-mail addresses, do you?
2)  Just think of these calls as if they were being made by inmates at a prison.   If the caller is not an inmate, then perhaps they should be
3)  if it's important enough your unknown caller should leave a message      
4)  if you happen to answer the call and the caller is a telemarketer, or is rude or pushy just say "hang on a minute" ( don't even wait for a polite opening ),  put the phone down, and later, hang up when you hear the dial tone.  

TIME is the most valuable asset to telemarketers so the longer you keep them on line the more likely you will be removed from the contact list.   DON'T TALK TO THEM !!!   It works for me !!

Am now able to blacklist phone numbers on our Ooma system and set the system to continuously ring.    See Ooma.com    Blacklisting also available on Verizon

This number keeps calling me

Called two times today. Left no message.  Very annoying to get these calls

Called 3 times today on my cell.  I don't answer numbers I don't recognize...they didn't leave a message.

Called two times today. Left no message. Who is this? Annoying to get these calls.

Unknown caller calling a cell phone.....let them get their own minutes !!!!!

Calls every hour...they hang up when I don't answer...who is this, and how do I get them their number blocked??

They call 3 times a day, but refuse to leave a message.
Anybody know what company this is??

Called and left no message