Airtel — Roaming 75 charge continuously added to my bill

Address:

New Delhi, Delhi

I have my airtel post paid no [protected] and at month nov-2014 I was used service roaming 75/m I paid it in my dec bill I got that it is continuously added in Jan-2015 and when I asked to stop then Care replied me to that will also added in your next bill feb-2015 when I told to care to revert my charges except nov-2014 they told me not possible but they never informed me for the plan will continuously added to bill I think that roaming plan is only for month plan so that they never informed me and when I going to stop I there are three month of roaming charges added to my account.
What is this company never given me information for such continuous plan and from the care such a bad peoples sit there taking badly only replying no not possible but airtel need to inform me the plan and continuation time need to confirm