Amazon India — Refund for my product

I bought a product from amazon OPPO F19 PRISM BLACK 6GB RAM, 128GB storage due to some issue i replaced the product but there was some issue with the replacement also for that product i had only refund option but they did not gave me the full amount which i paid 10000 for the replacement of my old phone & i paid 8990 from my master card but in refund i got in my master card 8990 & inly 8000 in amazon pay the rest amount of 2000 i did not got in amazon pay, please resolve the issue as soon as possible.