Vedant Computers Sales Private Limited - Seller forcefully canceled because I receive 90percent off

I successfully purchase GEFORCE GTX **** TI VENTUS XS *GB OC graphic card from www.vedantcomputers.com for ₹**** at **% off. I received an order confirmation email and another email stating I will be receiving my purchased graphics card soon. However, after a few minutes, I receive a call from Vedant Computers asking me to take a refund for this purchase as they made a mistake in pricing. I informed the seller that I made a legal and successful transaction/purchase on your website and I am not willing to take the refund and asked him to deliver the graphics card that I have purchased from this website.
I later receive an email stating that my order is cancelled and asking me for bank information for the refund which I have not acknowledged.
It's been one month and I just received another email within this month asking for my bank details.
I replied today that I will sue them if they do not give me my purchased product. Within a few minutes, I receive email from CCAvenue that refund has been initiated.
Vedant Computers had my money for one month and made interest out of it and now they are refunding my money which I declined from the beginning asking then to deliver my purchased GEFORCE GTX **** TI VENTUS XS *GB OC graphic.