I missed two calls from this number within the past two weeks and when I tried calling back it would go to a busy signal, even trying to call back several times at different times of day I always got a busy signal. Today I received a call from the same number, this time I answered it and said "Good Afternoon."... I didn't hear a reply so I repeated myself after which the call disconnected.

This number keeps calling me I don't know who it is please make them stop

Claimed to be calling about an insurance payment.  No insurance company has my number.
Blacklisted

received a call around 10:40AM today. no voicemail left.

"National Insurance" company.  The "new car insurance laws can significantly lower your car insurance rates." Very persistent even when I answered no multiple times.  I finally asked how many times I had to say "no" before she would hang up.  She quickly apologized and hung up.