Who called from 4052414006

Person identified himself as "the Kramer Group" but would not give a name. When asked what he wanted he hung up.  Called back the number and it was an add for Barack Obama....

Keep getting calls from this number. No one is there it seems, just dead air.

Get calls DAILY from this number. Sometimes several times a day.
Don't recognize it , so don't answer.
Never leaves message.
Would love to get it stopped!