Airtel — asking for airtel broadband connection payment though already paid

Website:

www.airtel.in/broadband

I am having a broadband connection of airtel for which i did payment on 30th january (6 month plan). Now again after a week, i got a call that i need to pay bill for other plan which i have changed as this is advanced rental service. It meant that whatever payment already did was wasted and i lost my money. I did ask to customer care before changing the plan and they mentioned i need to pay bill after 6 month of activation. They never mentioned my current payment will be wasted away.

Broadband id: [protected]_mh
Name: hardik jethva
Mobile no.: [protected]