I filled in all the details and got an email in reply. Next day I got a call from Sandisk, who asked me a couple of questions regarding the nature of the issue. Also I verified the SD serial number. Post that I got a RMA number in my email.
Next I had to go to Rashi Peripherals in my city (they are the authorised service center for memory devices in India for various companies). Once I reached there, I handed over the RMA number and got a brand new 64-GB micro-SD card. Saved almost INR 1500.