my dala 99

Im charged Rs 99 by vodafone for d2c_mydala_99 by vodafone in last month bill on 21/02/2015 And customer care is saying i have downloaded an application/service.
But i’m totally unaware of any download on my part .i think this is a fraud bill invoked by vodafone to keep post paid bills high as lots of customers are facing this issue and have complaint for same.