I use a non-yahoo address to post to groups. My posts do not show up.?

I use a Bellsouth address for my yahoo groups. Last July, my posts from this address began ending up in the spam file. The moderators would post them and approve me, but the same thing kept happening. I dropped all the groups. I just rejoined a group. I receive all the e-mails from others. However now my posts are not showing up anywhere. It shows that I have never posted. What is going on