Hi Kapoor,
The iPhone 4S isn't new anymore. I believe 5 new iPhones have come out since then. In fact, I don't even think Apple sells the 4S new anymore. Is the phone used or did you buy it factory refurbished from Apple or a certified seller? If you bought it refurbished from Apple, the battery would have been replaced and you would also have a 1 year warranty, I believe. If you bought it from a third party seller, such as from someone on eBay, you can contact the seller and more than likely get your money back. If you bought it from a friend or someone you knew, there's always the chance that you might get a product that isn't up to par. I'm always wary of buying used electronics for this reason. Sometimes people try to sell things when there is something wrong with the product and they don't tell the buyer about it.
I wouldn't blame the phone. Anything that is used can't expected to be just like brand new. I've never come across a defective Apple product in my lifetime. Apple is a great brand and you shouldn't base your prejudice off one product. I swear, all Apple products are good.
Another option is replacing the battery. You could send it to Apple or have a certified person do so.
I hope your issue is resolved. 🙂
