State Bank Of India [SBI] — Not received the refunded amount in my account

My name is mr. Himadri shikhar bagchi and i had ordered divya medhavati of rs 718 on amazon.in on 08/05/2020 and i canceled the order on 11th may due to personal reasons. After few days amazon initiated the amount to my card but i still didn't get the money. Amazon had sent me the refund reference number that is 814956 on 15/05/2020. But till now the amount did not reflect in my account so amazon told me to fill charge dispute form but i did not find any such option on sbi. I tried to contact their online customer service center but they are not operating due to covid 19. So, please kindly respond to this complaint it's very urgent. My card number is [protected].
Thank you sir.