No email delivery of messages to our large yahoogroup!?

For almost a week now my group has not been having approved posts delivered by email, or even moderation activity posts delivered via email to moderators. Posts can be approved via the group web portal page and do show up in the messages, but no one in the group is receiving emails of these posts. We are a large group (500+) and no one is receiving emails, even moderators. I've put in two reports to customer care, one last week and one today. We need this issue resolved quickly!