Airtel Digital TV — Change of Package before installation

Address:

Chandigarh, Chandigarh

i have ordered for Magnum1M790 plan and paid Rs.1790/= on line, which is yet to be installed and I intend to change it into Mega Pack 12 Month plan for Rs.4680/= and ready to pay difference amount of Rs.2680/= before commencement of connection. I tried twice on Customer Care number, but
nobody knows how to do it, even a senior executive, who asked me recharge online, which is for existing running plan, whereas I want to change my plan before installation. I do not know what type of customer service they are providing and to whom I should contact in airtel. My registered e-mail id is [protected]@gmail.com and registered phone 91+[protected]