I have gotten more than one call from this number.  When I answer I can tell it is some kind of automated call, the kind that makes you wait until a real person has noticed you picked up.  I usually just hang up before they come on.  I finally called the number back and got a recorded message that said  "Thank you for calling Discover card services.  We recently tried to contact you about a new service available.  If you would like to talk to a representative hold on until there is one available to take your call"