Consumer Redressal

I have some billing issues regarding my uses and the billing amount for the last couple of months. I am receiving bills more than my uses, showing GPRS uses which I have never used. So I thought not to pay the bills until my issues about the same got resolved since it was not the first time that I am receiving this kind of bills with false use details. I got a call from idea postpaid bill collection department (The number was 8481053172) on 20th February 2015 in the afternoon which i could not receive due to my busy schedule. After that i called back to the same number (8481053172) from another number (9674532420) and i asked in English "May i know with whom i am talking with? Because I have a missed call in my phone from your number", but I got reply in Bengali with a lots of abusive languages and slangs which I think under any circumstances is not acceptable at all, and right on that moment I have decided to go legal with it under my consumer rights.