Can anyone help me?

So, as always I recharge my sim with a ₹199/2gb per day play, as I almost always use my wifi..... But this time, the data worked for like 10 days and from the past 3 days my data is draining out. As we know that the data resets at 12:00 am midnight, I sleep before that and I turn off my data before sleeping, even if I forget to turn off my data, my wifi will be connected all night, and yet in the morning when I wake up, what I see in the Airtel app is, - 2gb data over in bright red. So I'm confused, I've been recharging with ₹49 from the past 3 days. Someone help me please! :(