Airtel — internet balance is empty without using

Address: 518/31, Gandhinagar, Walajapet, Vellore, Tamil Nadu, 632513

Morning 7:30 i turn on my data and send someone message in whatsapp and put my phone in charge
9 o'clock i take my phone and open facebook video not loading and a message came i used 💯% data
I shocked i don't allow any auto update
Not turn on hotspot
My balance is gone empty
I call the helpline she simply said my system showing you consume the data
I said to her the above details and i said connect with higher authority and she a
Said this is not that much think to connect higher authority