Indian Bank — online failed transaction but money is debited

I have paid an amount of 1282.05/- for a institute (Indian statistical institute) examination fee but, transaction got failed and the money got debited from my indian bank account at 19.03.2020.
I am unable to get my refund and it's been more than 20 days, since i thought money would automatically get credited to my account but as it fails to happen, i am facing problems and hence came for the complainant, that's why i kindly request you to see this matter and resolve it quickly
Thank you.