Idea Cellular — idea cellular - wrong bill charged and harassment;[protected]

Idea Cellular — idea cellular idea cellular demand legal notice! wrong bill charged

Hi, i was using idea postpaid maharashtra connection (Account #[protected] ; Mobile # [protected]) till dec 2017 after which i ported it to idea prepaid haryana connection after clearing out all bills.

After 4 months, i am receiving the mail from idea asking for some balance payment due.. As i have already cleared all the due with my idea & there is no due then why idea is harassing me & my family by sending these emails.
I also check my idea app and called idea haryana and both tell that no dues are pending from my side.
In addition to this Idea #, I am using another Idea # and never have skipped any payment.
Please help in closing this at the earliest.