Idea Cellular — billing dispute for vas

I had free amazon prime subscription for 1 year according to my current plan. The subscription had an expiry date of 10 apr.
I sent a subscription cancellation sms on 9 apr and called idea customer care to let them know of the unsubscription as i did not want to renew it. I still got an sms on 10 apr stating that it has been renewed and that charges are applied to my next bill which will generate on 22 apr.
When i complained on 10 apr after receiving the renewal message, they said i need to wait till my bill is generated.
After my bill was generated, they said that i canceled it in the middle of the billing cycle and hence the charges are valid.

7 apr: i got an idea notification sms (Attached)
9 apr: i sent an sms to unsubscribe (Attached)
9 apr: i called customer service to unsubscribe - the agent informed me it will be done.
10 apr: i got idea notification sms that my subscription for amazon prime is renewed and that the charges will be added to my bill (Attached)
10 apr: i sent an email to customer service to dispute this incorrect renewal of the subscription (First email in this thread)
10 apr: i got a reply from customer service and asked me to wait till the bill generates. (My bill date is 22nd of every month)

The charges are incorrect as idea renewed the subscription despite of my request to cancel it.