Bharti Airtel (Broadband) — Wrong reminders on bill payment

Hello team,
I have a broadband connection (Airtel)- airtel fixedline id[protected]_kk
I had made the payment for the previous cycle on 7th may-2020.
(Reference number :[protected]; txn id :[protected].
Even the payment details are reflecting correctly in airtel app.
However, i am again getting repeated reminders asking me to make a payment on 28th may. For the ongoing cycle, payment due date should be ideally 7th of june.
I have sent an email to their customer care but no response yet. Kindly help in getting this issue fixed. I shouldnot be charged extra for no fault of mine.
Regards, sd