BSNL — Deduction of money from the balance on its own

Address:

Pune, Maharashtra

On my "pyari-jodi" mobile I purchased a top-up for Rs.200/-( actual talk time recd. is Rs. 175/-) on 18/05/13.
On 19/05/13 , I recd a msg.(SMS) from155223 that my account has been debited for Rs. 15/- for the service of "Hot-spot 15 services" and further I was advised that I must send a SMS - in case if I do not need this service. so far I have not given any reply.
First of all during my last about - more than 1 year o[censored]sing this no. I have not recd. such auto debits, and all of a sudden without my knowledge how "BSNL" can debit my account.
I am getting some unwanted "SMSs", - some sort of marketing , and for this I approached to the "Satara road-BSNL office" and I was told that if "you are not getting any charge debits" then it may be OK for getting these SMSs. So based on this I did not gave any complaint to the office in writting.
Now with this debit, I wish to register my complaint to "BSNL" and wish that the debit done shall be reversed back with intimation to me without fail.
Hope to get early response on this.
My land line no. is 24220788
Thanks