Cox providing selective internet. I cannot access Amazon.com, eBay.com and other basic sites. Can’t connect a fire tv because it connects to Amazon. No one at Cox can fix it. Where is this being blocked?

I am using a Mac without any anti virus program.  I have checked firewalls.  I have the same problem on all computers.  And other peoples computers used on my network.  Even the Cox workmen tried and had the same issue.