Airtel — cash back night data

I've subscribed for night cashback offer two days ago. I was supposed to receive 50% of the data used between 12 am-6 am but i didn't. I had subscribed twice when i didn't get the cash back in the morning yesterday but still the same result! I've both the sms confirmations that my night cash back is activated. I want to know why you send confirmation sms to a service when you're not able to give the service in first place. I want 50% of my used data back as well as per the plan. A quick response will be appreciated.
Airtel number - [protected]