These calls use VOIP so the number will constantly change. Typically they are telemarketers who work independently. In some cases it's for a third party electrical supplier. They use the greeting "this is so-and-so looking for so-and-so" so you don't hang up on them. They only need a little time with you on the phone to verify the phone number is good then they can hang up and they send your valid number to the electrical utility that wants your info to switch your provider. They have no idea who you are, they just have a computer random dial numbers to find out good numbers. They see what area code you're in then they call and give you the sales pitch based on the utility in that area making you think they have your information and know where you are. The reason I know all of this is because just for fun I called the number back that called me using *67 first so my number didn't show at their end. A man tried making it sound like he knew my information but when I pressed him for details, he said he didn't have my paperwork in front of him. He asked me for my phone number, which I wouldn't give him so then he asked for my area code. Red flag. I told him an area code that I didn't live in and he started going into his speech about how he could save me money on my electric bill by switching from xyz supplier to abc supplier. I told him I wasn't interested and hung up. BOTTOM LINE, IF YOU DON'T KNOW THE NUMBER, DON'T ANSWER. IF IT'S IMPORTANT THEY WILL LEAVE YOU A VOICE MAIL AND YOU CAN CALL BACK.
Left a message asking me to call back about my Columba Gas bill. "Be sure to have your account number handy from your latest bill." The message is worded to imply she is actually from Columbia Gas. These unwanted calls are out of hand.