I received a couple of calls from this number and they said they were from "cost you less insurance". Whrn i called back it sounded like a call center and the person answered with " hello".

up yours

Suspect scam.

They left voicemail.  They said they were calling from my insurance company.  At the start of the message they mumbled something ("This is gbldgk Insurance Company"..)  and supposedly said the name of a company but I listened to it several times and the "name" seems to be deliberately muffled (everything else in the message is perfectly clear).  They're claiming that they sent mail to me that got returned and  they want me to call back and provide my mailing address.  Yeah, riiiiiiight.

note: I've had my phone number for over a year; unlikely a company would be calling a previous owner of my number.