"He was been trying to call for the last 3 days and we are not taking his calls. Does anyone have any advice?"

I have a listing of about a dozen numbers in the Blocked Calls list for our phone service. And they are making nomorobo available. If you enable this, it rings both your office and the nomorobo server once, and if the number is a known scammer, it stops ringing for you. It's like a virus checker for Phone calls.