Oneplus mobiles 1500 discount through AMEX

https://www.amazon.in/b/ref=s9_acss_bw_cg_CEEX_2a1_w?node=14155105031
OnePlus – American Express Offer FAQs
What is the offer?
Get Rs.1,500 Instant Discount on AMEX Credit Cards, on purchase of OnePlus 3T and OnePlus 5 smartphones from 27 September 2017 to 29 September 2017. The discount is valid on the purchase of one phone only per card.
How can I avail this offer?
Just go through the normal purchase process and checkout with the product only. Use your AMEX Card to avail the discount and pay the net amount. Please note that your purchase must contain only the OnePlus 3T or OnePlus 5, i.e. no other item in your cart.
What is the maximum discount that I can avail?
This is a Flat Rs.1,500 discount on the list price. So, the maximum discount possible per card account across Amazon.in Site and App is Rs.1,500. The offer is valid only once per card.
Is discount applicable on AMEX Credit Cards?
Yes, the discount is available on AMEX Credit Cards only.
Can I avail discount on credit card on EMI?
No, the discount is not applicable on Credit Card EMI.
Can I get this offer along with Exchange?
Yes, the offer is valid even if you buy with exchange.
My payment failed while placing the order, will I be eligible for the offer?
If your payment failed while placing the order, Amazon.in gives you an option to revise your payment. If you revise your payment, you will be eligible for the offer – however, you will receive the offer in the form of Amazon Pay Balance Cashback to your Amazon.in account by 29th November 2017.