We can get still less…exchange some phone and 5000 will be added to exchange value and now pay with ICICI Amazon pay card..which gives 5% CB ..
Eg… X phone has exchange value as 3600
With one plus 9 pro : 8600(5000+ 3600)
Coupon : 5800
Pay remaining 59999 – 5800(coupon) – 8600(exchange) =45599
Pay 45599 with amazon pay card and you will get 5% CB for 45599