Thanks everyone. To wrap it up, I bought the connection on Saturday morning and received a response from the seller in the afternoon that the application is being processed and installation will be completed within 24 hours.
However, I didn't receive a response from Tata Sky on Saturday, so I wrote to the seller today morning and he replied immediately with the customer ID. Thereafter, I contacted the Tata Sky helpline following which the installation and activation was done within the next 2 hours.
It is the Annual Ultra HD package with 1 year HD Access and the price came to around 9k after using 5% Amazon gift certificate discounts. All in all, a good experience so far.