Yes no one held a gun but there are facts that need to be disclosed before a sale, facts that the seller very well knows would have had bearing on the decision of the buyer. Concealment of information is not covered under the pretext of whats written on the back no matter how exhaustive the list may be.
True everyone signed the contract but the point that just seems to be lost on you and many others who are so quick to jump to the conclusion of blaming the customer, is that the contact was signed with the implied understanding that apart from price nothing else would be revealed in the coming days that would have a significant effect on the product, enough to make the buyer change his decision (which happened and the buyer was locked into the contract)
Had Atlas given the option to refund the booking amount then there would not have been a strong case but here Atlas is forcing you now to switch over to the 1.8L...do you understand the difference... THEY ARE FORCING YOU TO BUY 1.8L but lured you through the 1.5L option.
Lastly a toothpaste is worth what Rs. 50-100 and a car is worth what 2.5 million.... hahahaha your comparison is hilarious. You have to compare like things together otherwise going by your naive comparison buying an aeroplane and a car are also the same thing ? lol