Unhappy client

I had downloaded telegram before on my mobile, deleted it a month ago. Currently I am reloading it, I'm am surprised that I am being told that verification code it is sent to my Telegram App and my number is correct. Now according to privacy T&C's indeed my personal details are not protected....who is using my telegram...I need to log in to my school groups. I have sent an email, no response from telegram. No this is indeed poor and unsafe platform