visa refuser

please is it possible for the embassy to refuse visa with out stamping inside the passport as refuser or you use your verbal mouth?
because I was there just yesterday for my passport as student visa.
first the Lady at the counter said my bank statement wasn't up to date
I have to update it which I did. after receiving the passport yesterday she said i was been refuse the visa what was the reason she said no reason

but i know for sure all my document is in order and valid , can you please explain to me what's the cause