Well, as I had feared, my luck just ran out. SMTP is acting up again and when I ping it, it loses most of the packets. Unfortunately ping does not work with POP and when I try to receive mail it hangs up, fails to connect and takes an interminably long time to download. Even signing in to this forum has become a chore. My first attempt gave a "There was an unexpected internal error. Please try again." message. Retry hung up. Then I refreshed and after several minutes of wait it finally connected.
Anyway, I have given up. As far as I can tell, this will be a perpetual headache from now on and will never get fixed. I have chatted with tech support several times and it was a most aggravating experience. I never had such a frustrating experience in twenty years.