Vodafone MY-DALA deduction

I am using vodafone no. 9643027650. Today evening I received a sms containing this – “Dear Customer,your voucher no for WIN Samsung Galaxy Note 4 Bid Deal for Rs 99 is 17726429761512. Your total bids purchased so far are 99.You either win or get 100% money back in points. Total vouchers valid till 2015-03-17 are 99.Call at 011-43444498 for more details. Enjoy the deal!”. Rs 99/- deducted from my account. I called Vodafone care four times regarding the deduction. They replied differently. This is cheating. I didn’t bid for anything. Even I didn’t know anything about MY-DALA. In the internet I found many people faced the same problem. Please resolve the issue.