Airtel — balance deducted 150 rs by saying whatsmob service that I am not aware

Airtel has deducted 150 rupees from my mobile balance. SMS Is as follows:-

"WHATSMOB service has been activated @ Rs 150.00 for 30 days. TxnID N[protected], 30 Apr18 10:00. Service will be renewed after validity expriry. To deactivate, call or SMS STOP to 155223. More services? 56789."

I want my money to be refunded back to my mobile number [protected]. I called Airtel customer care as well. Customer care representative told he will connect to his supervisor and asked me to wait. I waited for 5minutes, but nothing happened.
Airtel is really cheating their customers.. Please get the refund of my money