@Sushubh I paid the full amount and I got the discount. Maybe it depends on type of hdfc card because as soon as I entered the number it notified me that a discount has been applied and total cost went down. I used hdfc millenia.
i do not have a s20 fe. i returned that phone last year after a lot of effort last year coz of wifi issues. my s10 lite is more than 2.5 years old now. it should still get android 13 and is still running great with quite decent battery life. definitely worth more than a new 10K smartphone if i ever need to buy in near future.
i waited for around 20 minutes for the chat guy to check about the hdfc issue. he did not have any clear answer for me. but did confirm that discount should appear instantly if the offer was applicable on card so that helped sort of.
just remembered i had ordered s10 lite in feb 2020. and even got it replaced once on flipkart because of display issue. and it was just a few days before the whole covid mess started. the phone spent most of its life in lockdown.