ACT Broadband - Unfair charging on internet connection

On Month of *st April **** we stopped using the internet so nice we have a prepaid connection and explicitly called customer care and informed that we are not using the internet. So on the month of July, we resumed our connection by paying around *** Rs after **th. But now ACT people called us and make us pay this month bill again. As per ACT, we used the net on April but we did not use.
So please return the *** Rs of unfair charges
Internet details:
ACT User name: Avinash / Srinadh
ACT Account number: ************
Registered Phone number: ***** *****
My wifi user name: *******
I have raised a ticket and escalated to the nodal officer as well but no use. They don't even respond. Here is the ticket reference. SR**************