Tata Neu — Not conversion of no cost emi as promised in the app while placing order

I ordered a led smart tv from Tata New Croma app on 9th July, 2023. In the app the price of 9899/- was showing if I buy it using no cost emi using hdfc credit card, otherwise it was showing 8899/-, if the same is bought by paying at once. I made the purchase using hdfc cc ending 3356 and opting for no cost emi. However, when the statement of hdfc cc came, it asked me to pay the amount 9899/- at once. Since 22nd July, 2023, I am contacting both tata nei and hdfc cc and they are blaming each other and none of them providing any resolution. Every time they are asking for 7-10 days/72 hours etc for resolution but is not coming up with any.