I think a lot of people have lost some - I know I have.
I have looked through all the admin bits I have access to and can see no mention of post counts anywhere - it doesn't seem to be something that Mods have any control over.
I don't suppose any of you know how many you have lost and if that correlates to the number of posts iyou made in the story threads? It may be that they have gone because the story posts have gone but we can't have massive posts like that just locked and sitting there using up space otherwise we will be closed down by the hosts again!
Will keep on investigating but at the moment I can see no reason for it.