Comcast blocking Google mail servers, failing even with Comcast sending servers: When will you fix this?

Over the past three to four weeks, I have experienced a worsening problem.  Sometimes, I will never receive emails that were sent using a Goolge mail server.  Also, when I send mail from a Google server, sometimes a Comcast recipient will not receive it.  Examining the delivery failure messages indicates that Comcast is rejecting email from specific sets of Google servers.  Those may change from day to day.  The problem is intermittent because one never knows whether Comcast will reject the specific Google server selected to deliver the message.  Less frequently, I have even had emails recently fail from one Comcast account to another.

Let's get past the usual low-level issues.  These problems occur regardless of the email client used, the operating system used, or the mail protocol used.  That makes sense because the "lost" emails never show up on the Comcast server.  Apparently, others have experienced these problems as well.  This state of affairs is unacceptable.  Right now, it is the case that I never know if an email I send will be received at a Comcast address and I never know if an email sent to my own Comcast address will show up.  I repeat that other users, perhaps many, are also suffering with this poor service.