ALWAYS follow up your telephonic complaint with an email ( detailing your problem ) to care.xxxx @ airtel.inYou will get a written acknowledgement.Para two :Sometime back, after tariff plan change, I wanted my NU Free Should Not be recorded in my Usage Data ( Airtel SelfCare Page) as earlier done.After number of Phone Calls/ emails/ and technical help assistance on line in Self Care pageI said I am discontinuing the the BB Connection.Customer retention cell called me to wait for action. And from Bangaluru Airtel, I got another call and when I gave the details , the usage meter was set as I wanted !So a written complaint is always advisable.Airtel has competent technical staff, but not for CC.It is more than a year I called CC or sent email to them reg BB/modem!A Telephone line complaint by me, recently was set right within 6 hours. They never commit in writing in email, other than routine replies .By the way I also never called CC of BSNL for more than two years!! no problems!