Flipkart - Package not delivered as promised and According to policey the did not give me the replacement phone

Hi.. I ordered a phone on Diwali sale by Flipkart on Tue Nov **. And it reached on as promising date ** Nov .with this product realme gt master edition has some camera issues. so I talked to the customer care and he said that u will get new phone according to our * day replacement policy when we pick up this phone. despite that they gave me refund and I ordered it on Diwali sale and now that costs me **** extra and they refused me to give new phone. Please sir I don't know too much about that how should I proceed and am I doing right or wrong but please help me . Very bad service and also the seller's behaviour is not good they charged me delivery charges but I picked this product on the store . They refused me to deliver this product on delivery location. Please