Airtel — Employee cheated for sale

Address:

Bharti Airtel

I am a customer using your broadband and mobile connection under Airtel black.i have this connection few months back in which airtel executive came and confirmed the postpaid plan 499/- that maam you will get only bill of Rs 589 under which one mobile and broadband will work.but when the bill came it was 1239 Rs of one month.As the bill the executive has cheated me .so, please help to waiver out the rest amount except 589 so I can exclude my mobile from broadband and use it in prepaid.
It's my request to do the needful on immediate basis.
My number in Airtel black-[protected],
Broadband-[protected]_dsl