Airtel — international roaming activated without my consent

Hello,
I was travelling to Brazil from 5th November for my Business Trip as i was to use the local sim card throughout my stay there. However, being an Airtel postpaid user, i called Airtel Customer Care on 5th Dec 18 & activated the IR Plan @ Rs 3999 for 1 Month . It is pertinent to note that here, I have clearly said that i want IR Plan for 1 Month only but on 5th Jan 19 i suddenly received a message that again my IR Plan of @3999 has been activated in my No +91-[protected].
I have never asked for renewal of my IR Plan then how come its get activated again . I have received a Bill also of Rs 9790 (Including Jan month IR Rental 3999).

IR Roaming in Jan 19 activated without my consent & approval.
Now who will pay the amount of Rs 9790 ?

Are Airtel really authorised to activate services that are not consented or asked/requested by the user?

I am calling to Customer Care but not getting solution here.