Bills raised by Idea even after deactivation of number

I used a idea post paid connection last year and after final payment did on 22.12.2016 .My No deactivated and also we confirm several time to idea stores that pls close my No.
But till date they raise bills .And finally last Saturday the harrased me over ph that i have to pay 1046 further otherwise they will go legal .As a common person today i submitted further the amount.
They till not confirm whether my No closed from there end nor any information except my deposit to them. WANT A SOLUTION..AND NEED MY UN USED MONEY BACK FROM idea.

Suchandan Saha
Rabindra Nagar East, Kolkata 700153, West Bengal
Email: sxxxxxxxxxxx6@gmail.com