You said you saw 主贴不存在, that's a different situation, as described below:
User A posts a posting #1.
You see posting #1, you want to reply. You click the reply button and start to type your text.
User A deletes posting #1.
User A posts posting #2, with the same text, or slightly different text (more likely, usually User A wants to change something)
You finish your typing, you click submit.
Your reply is for #1, which does not exist anymore, so the system tells you 父帖不存在。
However, you see the posting is still there. You don't realize that it's in fact a DIFFERENT post. You think mistakenly that you are blocked. No, you are not.
User A posts a posting #1.
You see posting #1, you want to reply. You click the reply button and start to type your text.
User A deletes posting #1.
User A posts posting #2, with the same text, or slightly different text (more likely, usually User A wants to change something)
You finish your typing, you click submit.
Your reply is for #1, which does not exist anymore, so the system tells you 父帖不存在。
However, you see the posting is still there. You don't realize that it's in fact a DIFFERENT post. You think mistakenly that you are blocked. No, you are not.