Airtel — Issue with data usage

It is to complain about the data drainage on my airtel connection. Day before yesterday I recharged add on pack of 148 of which airtel gives us 18gb of data and with that data and my daily data of 3gb I watched youtube and social media for an hour or two yesterday and today and all my data of 21gb are gone which left me so confused as I keep track of my data usage and I am damn sure airtel is looting its customers in this way as it has been happening with me for a year and half and after trying their every number of customer care i am either unable to talk with a customer care or they provide some silly excuses in this regard. Please and please look into my complaint asap as I am very much fed up with this as I am not able to change my network connection either as all other network companies have weak network connections in my are. Thanks and regards.