We received a call from this phone number claiming to be United Health Care for a second time.  My husband does have them as his insurance carrier.  They wanted to ask a few questions about his medical history and claims that Medicare requires UH to ask these questions.  I hung up on them the first time.  Today they called again using an automated phone message saying how in a few days they will call him back to ask the questions.  It also gave a 1-855 number to call them.  We will call them back using the number on the back of the card.  Don't know if the number they gave was a match as I didn't have a pen available.  Everything else they have done in the past has been through the mail, like mail back or call to verify your street address as we like to use the PO Box info.  But for some reason this Medicare/United Health combo insurance needs a street address because you don't live in a PO Box. Another letter was for to prove he had prescription coverage the previous year.  Again they were letters. Always best to use the number on the back of the card.  Never call back the number they call from or one that is left in a message.  Don't understand why they can't ask all of the questions at once. This is what is alarming.