Airtel — disapproval of recharge benefits.

I am an airtel prepaid user, and has been using it for the past 7 years plus.

Recently, on may 1st 2017, i received a message stating that a recharge of 399 will give internet benefits of 1 gb per day, and free local calls for a period of 56 days.

As per the message, i opted to pay 399, other than the usual ₹345 which provided me the same benefits for 28 days.
The recharge was done on may 14th, but the benefits were not provided, and a call to the customer care reported that the recharge was invalid, thus wasting 399 of my money.
I require either a full refund or a usual benefit of 345 for 1 month, else i will have to opt out and port my number to other providers.
Hope the issue gets resolved quickly.
Faithfully,