Got a phone call at 8 pm hung up after 4 rings did star 69 and got this number 551-226-6775 , did a reverse lookup and they could not identify the number, Telemarketing scammers. Best bet is to set your rings to six and they will hang up on the fourth ring. Anyone that knows you will let it ring to the answer machine or you pick up on 5-6 rings. I am on the no call list but that does not help.
I've received numerous calls from the same number. I also agree on the Do Not Call Registry - I've reported numbers in the past, several of the numbers multiple times, to no avail. I canceled the voicemail service I had from Comcast because of this kind of problem and that helps. If I see a name/number I recognize on the Caller ID, then I know it's a legit call.