Help to sue Amazon.in

I had an account with Amazon.in recently as I need to order some stuff for my kids. I was able to order 2 items but I returned one from it and refunded the payment(1199 rupees) and had it on my Amazon Pay balance. Then I orderef another item, bottle sterilizer worth 3370 rupees. I used the Amazon Pay balance to pay the item and my debit card. I was about to enter the password or pin of my debit card when my internet stopped working so the page didn't load successfully. I reloaded the Amazon.in application and then it asked me for my Amazon.in account password which didn't work. I tried logging in multiple times using my email address and India number registered on Amazon.in until I reset the password as well for multiple times. I gave up on logging in and tell myself that I'll try later. We got home from hospital and I tried logging in again but failed. I checked on my email and got one from Amazon.in telling me that my order was cancelled and they out back the Amazon Pay balance. Then I got another email after few minutes that my order was placed and Amazon.in deducted my Amazon Pay balance. I was confused that time so what I did, I tried checking my bank account. There I saw, Amazon.in deducted the remaining balance of my order without me authorizing them or putting any pasword or pin. Amazon.in took my money and noe they sent an email telling me that my acccount is closed as I've used an invalid credit card. How can I get my money back? Can you help me with this?