Received two calls from 720-728-0060, Denver CO no name, at 3:10 and 3:11am PDT. Calls were answered by us. No one on the line. We have ailing parents and were concerned that these were emergency calls. At 3am you're not reading the Caller-ID. The number is now blocked and a nuisance complaint filed.

Received a call at 7:03 am. Caller ID said FAXBLOCK,ME. I let it go to voice mail but they didn't leave a message.

There are many complaints on many numbers about the "service" calling itself "FAXBLOCK.ME"
It's basically a business that sends fax blasts out and also pesters people to put their numbers on the business' own Do-Not-Call list - even though sending fax blasts is illegal when the recipient hasn't authorized it in advance.

Google the words
faxblock.me site:800notes.com
to see a long list of results. If you can block an area code and exchange number, then try blocking
720-728-xxxx
303-536-xxxx

"fastblock.me" is the website for that business.

Unless the entire city of Denver is calling me, the  only ID  appearing is Denver CO and I know there is no one with that name. It is the typical, spoofed number.  Blocking does no good, they work around it.  I now save these humbers in my contacts (1000's of slots available) but , preface them with a Z so that the next tiem they call, I know it's a scammer and ignore then erase. Why save ? I've used all of the 350 slots available on my blocking equipment.