Just now they deleted my first post because it's 'off topic' I posted a short phrase that's the reason, stop posting short content.
No, that's not the reason your post was deleted. Short and concise posts addressing the topics at hand do not get deleted. But copy and paste or repeated short comments will always get deleted.
Even a higher ranks,if there's a lot of deleted posts have been made,is there a chance of their accounts getting banned?
I haven't read in the rules anywhere here that says a certain number of deleted posts could get one banned without first being warned. One must get a citation or warning before one will get banned. Everyone here, at one time or the other, has got their posts deleted, including yours sincerely. It's not an omen to getting banned at all.