Idea Cellular — invalid data roaming charges

Address:

412114

Before my travel abroad, I activated international roaming on my phone and had also asked the customer care to de-activate mobile data.
They simply asked to do so via the phone settings. I have followed the same instructions - mobile data and roaming data are switched off in the phone settings right before and since my international travel(attached).
I gave them the screenshots of the phone settings as well as the mobile data usage which shows 0 bytes for the dates they have charged me gprs charges.

I have exchanged multiple emails with the customer care, re-iterating that I have provided screenshots as proof.
I called their customer care team which wasn’t helpful and they again directed to send an email.
I raised a complaint which was marked resolved without explanation or call back.

I need clarification regarding the gprs charges on my bill invoice dated 15th Aug and 15th sep.
I need to know why I have been charged for data usage in my last two bills even though it is switched off in the settings as instructed by their customer care team.

I am very much aware that roaming data has very high charges and made sure to turn it off before my travel. Inspite of this, I was shocked to see the phone bill amounting to around 4k INR
I paid off above bills in order to avoid late fees but I am still seeking an explanation and refund from Idea.