Airtel — no sms sent, yet 1.5 deducted from main balance

My airtel number is [protected]. I sent no sms on 5th nov at 11.20pm, yet ₹1.50 was deducted from my main balance quoting sms sent to a random number [protected] at that time. Airtel is cheating me by deducting money although i did not send any sms to any number. Customer care went unanswered and my money was not refunded to my account. I want a refund for an sms that i did not send else i would shift to another operator.