Why do internet filters not work?????

Why can't Cox block these emails from EVER reaching our inbox OR spam mail? Cox servers are receiving MILLIONS of spam containing certain key words in the from and/or subject lines: CBD, KETO, CONCEALED CARRY, CANNABIS, MED, PHARM[use regex for anything after PHARM], MCDONALD'S GIFT, AMAZON GIFT, etc. 

There is some major group of spammers using affiliate marketing partners and making millions of dollars by Cox allowing their spam to get through to us! 

Cox - where are you for your customers! This is basic spam filtering - when I tried to forward to cox spam report, you recognized it was spam and would not allow it to go OUT, so why can't you stop it from coming IN? Why do thousands upon thousands of your customers have to set up the same individual filters over and over, when you know this is spam and could easily block it at the server level. Why do we have to set up our own filters for flagrant violaters that are sending millions upon millions of spam emails!