Idea Cellular — I have already paid the bill and i switch to another network but idea office can call me my bill is pending why is this possible

Address:

205001

Idea is a very chep company...
Because i was a regular customer of idea at 8 years prepaid and 3 year podtpaid user.. I have some network problem so i complaint in idea customer care but no resolution i complaint again and again but same condition no resolution. So i monthly paid the bill and decide switch to another network.. When i done port my number to another network 1.5 month later idea care call me that my bill is pending worth rs. 9621.00
But my plan is rs 1299 unlimted how can possible is that my bill is pending when i paid already the bill. I was using the 1299 plan since 3 year no problem in that time and my bill is not much more then rs 2000 above with tax include..
I have proof that i am paid my bill and i am not a defaulter but company harresment me to give the faulter bill and i told him that i can paid any bill that he asked that i gave him rs 3000 and he adjust the bill but i have already paid the bill why should i have
I have all online paid bill
Receiving