Bsnl gsm
Isd missed calls being charged

I am having recurring problems in isd miss calls.i usually give a miss call to my parents in dubai, who then call me back this is how we used to communicate for the past 4 years, last year when i ported to bsnl, thats when the problems began -when i call i can hear the phone ringing but after three rings when i cut, i rescieve call charges for the ringing period, thrice i complained and thrice they returned my money and it is normal for another month now its started again and now i cannot even get through customer care.pls do something.