For reasons mysterious to me, combox entries sometimes go to the spam filter. The spam filter frequently has hundred of combox entries and I have no time to pore over them looking for stray entries. I just empty the spam file now and then and flush hundreds of entries down the memory hole without reading them (though I do confess a secret love of the occasional weirdly incoherent spam bot pseudo-praise (“Your site is full of good information and because you have many good issues and excellent layout I are bookmarking you!”)). But the basic rule of thumb is: assume I never saw your post if you commented and it disappeared. Keep trying. There are some people who have been banned. But chances are pretty good you are not among them if I’ve never told you so. Odds are good you are just a victim of a software glitch. Keep trying and you’ll get through.