This is actually Discover.
This is a scam. Discover will never call and not leave a message. You should always call back only the official number listed on a company's website and never give out your information unless you originated the call to a trusted phone number.
Just called Discover about this number calling. They confirmed this is a valid number.
This number has called me two times a day for the last three days.I am also on the DNC list.I picked up once with no response.