3 isn't many. Just don't post consecutively in the same thread within 24 hours. If you think of something new to say and your post is the last in a thread, simply edit the post to append your new thoughts to it (if its been less than 24 hours since posting).
It seems he is talking about post(s) deleted from his other account(s) after reading the bolded part.
I've had many posts deleted. Once I reposted a deleted post and the moderator changed the text. Now with this username there have been no outright deletions, but a moderator combines any two posts into one then sends the message
@OP, it just means you broke the rule of no consecutive posts and regarding the post deletion and not from this account doesn't mean these are not breaking the forum rules, it just means yet to be reported.
Anyway I recommend you not to post the deleted posts cause it can lead to ban for plagiarism if you're doing it from different account. If you think your post has been deleted without valid reason then bring attention to why there has been a mistake cause there are few incidents deleted posts were retrieved later once it's proven no violation found.