about my credit on mobily

every time my mobile close then I found a message that my credit is  deducted from my mobily card and this message come your last call charge where as |I did not call anybody or send a message??Please stop this service . I will be thank full to you. From the last 1month this is going on. I am fed up with this continuous disturbance....plssssssssssss pllllllssssss stop this somehow ...im sheila this my number +9665484559