https://www.amazon.in/h/rewards/dp/amzn1.reward...
To unlock Flat 100 back on Amazon Shopping, follow the steps below:
1. Place a successful Amazon.in order between 31-Jul-2021 06:00:00 AM to 05-Aug-2021 11:00:00 PM of minimum order value ₹299
2. An email notification with the URL of the unlocked reward will be sent, once the transaction is successfully completed. Upon receipt of such notification, you can ‘collect’ the unlocked reward for future use.
3. You can view all your unlocked reward under “Your Rewards” section
4. This reward can’t be clubbed with any other offer. If you’ve other unlocked rewards, you’ll be able to redeem the reward that gives the best cashback on your purchase. Rest of the rewards can be redeemed in subsequent purchases