Basically I replied to their posts by saying, thank you so much this was helpful.
Just like now for example, maybe later this thank you reply might also be removed, but I hope you will read it before it gets removed
You're probably spamming "thanks" or "thank you" posts on your thread. Probably your best bet is to quote everyone on a single reply and thank them all at the same time, in a single reply. Though I'm not completely sure if this is indeed whats causing your posts to be removed, since I can't view your deleted posts.