Bangalore Electricity Supply Company Limited [BESCOM] — Fake bill iussed at bangalore one office

Last month I had paid my electricity bill at Bangalore one office and this month that amount as again added to this month electricity bill
When I went and enquired about it
They said that the person who as working here as given u fake bill that it shows u that the amount as been paid
Now who will take responsible for that
They are saying us to pay the money again