Did Comcast disable it's spam filters or did I just get email bombed by a malicious bot?

When I got on my PC this morning I was shocked to see that I had over 300 new emails in my inbox!?! And almost every one of them was sort of spam, meaning I didn't ask for these emails from strangers - a bot started signing me up for random websites and newsletters at 4:51 am this morning, the first blast ended at 6:12 am, then I got another much smaller blast of them from 10:26 am to 11:25 am - I have a feeling I'm going to be fighting this bot for months! Spammers and ID thieves have had my two Comcast email addies for several decades - I created both in 1993 when cable was run to my house, so why this just started happening I have no idea. All of the garbage was sent to my primary Comcast email addy, and although some look like legitimate websites (not gonna click on any links to find out) over 50% of them have senders or subject lines that any spam filter should have recognized - I mean a bunch of them came from countries all over the world and the subject was in that language, not English - in all the years I've had Comcast email I can't recall EVER getting an email (spam or not) in a foreign language. I selected every one of them in a browser using the Xfinity webmail page and labeled them spam, so hopefully the sites that have already emailed me will get blocked, but if Comcast disabled their spam filters I'm really [Edited: "Language"] - what can I do to block these? I have legit accounts with over 100 sites so I'm not going to spend all day putting every one of them in my "safe senders" list in WinMail, and I can't use the "add people you reply to to your contacts" in webmail because I never respond to emails from the webmail site, I use POP3 to download them from the server and I set up WinMail so they get deleted from my webmail inbox 24 hours after they're downloaded. And please, no suggestions to get a new email - both are 32 years old and every person I know or do business with has those one of my emails.

P.S. The Xfinity webmail is going away anyway when I get switched to Yahoo email so it's not worth spending any time trying to filter them on the webmail site. 

P.P.S. Been googling how this could have happened and how to stop it - appears I can't? Lots of people on Reddit say it can mean one of my CC's was stolen and the spam bomb is meant to stop people from finding valid CC transactions via email alerts - I get them for every card every time they're used for any amount of money. At 5:07 am this morning I got an odd email from Synchrony Bank, which sponsors the Amazon Store card, which isn't even a CC, as it can only be used to buy stuff on Amazon - below is the subject line - I'll check with Synchrony to see if my card is compromised but I've gotten this exact email before and when I logged into the Synchrony website there were no actual charges so I didn't cancel the card - might need to cancel it and set up Synchrony to use a different email than the one that was bombed this morning.