BSNL cellphone service
Deduction of 20 rupees without any call

On 15th Oct time around 5:45pm... One sms came " Your last call rupees 20 and current balance is 164.56 only ". But as far I remember I hadn't any call before that and none of my friends or any relative used my cellphone... So i want to know that who mad this call and to which no... kindly provide me in my mail

Thanking you once more

Praveen