Unsolicited service and deduction of charges from monthly phone bill

I am surprised to notice from my bills for the past several months that a sum of Rs.170/= is being charged every month towards a service called 'music on demand' for which I had never requested.  Moreover amount of deduction is shown against an item 'one time charge' (!) and yet the deduction continues every month.  It is quite baffling to see this type of cheap methods adopted by BSNL to cheat customers.  Since I am not in the habit of scrutinizing my phone bill so minutely, I could not detect this fraud till now.  Please arrange to immediately reimburse the amounts deducted against this head and explain why I should not approach the consumer court for this sort of arbitrary charges by BSNL in the guise of BSNL-Hungama!  My phone number in the monthly billing of which this malpractice is done is:  25533027.