Airtel
Cricket Daily Pack is not being unsubscribed

I had subscribed to the Cricket Daily Pack Service. I had received a message saying "Congratulations! You have been successfully subscribed to Cricket Daily pack service. You will be charged Rs7/week. To deactivate Sms UNSUB SWCUP to 55383."

I wanted to deactivate the pack so I smsed UNSUB SWCUP to 55383 and I got a message saying Invalid Keyword.

This is wrong and I don't want to be charged for this service.