MTS / Sistema Shyam TeleServices [SSTL] — Mts data card payment issue

Address:

600100

I used mts mblaze data card. (Num: [protected])
I have raised request to close my connection and i paid total outstanding amount before raise request.
Mts customer care employee said, to complete this request they need 7 days of time and i should not use that device in that 7 days.
So i did not use that device in next 7 days and my connection was closed. But now mts is demanding me to pay amount for that 7 days.
If i am calling customer care they are not clarifying my doubts and more over they filed case on me for due amount.

My questions are : 1) as mts customer care said, i did not used that device in 7 days. Why should i pay amount for that 7 days?
2) if they take 20 days of time to close a connection means, do i need to pay amount for that 20 days?
3) taking more time to close the connection is problem with me or mts?
4) why mts is talking 7 days time to close a connection?
They are continuously calling me and sending messages to me, this is causing mental pressure to me. If they are able to prove that mistake is from my side i am ready to pay the amount they are asking.