Bharat Sanchar Nigam [BSNL] — arbitrary balance deduction and unethical behavior by the call center staff

I received a call at 10;44am on 2nd sept, 2018 with the number [protected], within 10 seconds of receiving it i disconnected the call as soon as i came to know that it is some sort of advertisement call. The moment i disconnected the call i received a text which said that i have been subscribed to some service and a balance of rs 30 was deducted promptly from my account without seeking my consent. Such malpractices have become quite rampant and the bsnl staff refuse to take the accountability of the same. When i asked them to lodge my complaint they disconnect the call.
Something needs to be done in this respect and this situation demands an immediate action. And i want my refund of the said illegally deducted amount.