Almost certainly the problems are down to your ISP . . it's something we know well in the UK!! That's why I currently access Newsgroups via Remarq (which I prefer to DejaNews) - it may take longer for messages to arrive but at least (almost?) all of them do.

[Yes, I have compared "delivery" via an ISP with that via Remarq; with r.m.f. up to about 50% of messages were not making it through our ISP; on cam.misc as many as 80% of messages failed to make it.]

Or as a sig in my part of the world used to say "The Internet is full - go away"

G.