Patanjali Ayurved — regarding exchanging the product, refused to provide bill, shop remains closed

Took a product of patanjali shampoo, the shopkeeper handed some other product (7.30 pm), took some medicine as well, asked for the bill didn't give the bill, reached home found the shapmoo was not the same i asked for, went to exchange it (As the shop is very near) the shop was closed (4.15 pm, 1.00pm mostly it remains closed), thus could not return it, i found shop open and went for exchanging, they refused and say its not in our policy?? What the policy is how a customer would know?? That too you don't provide bill and moreover these shopkeepers they misbehave in such a manner they say you should have taken the bill, you dont ask for the bill we won't give the bill (And moreover the shopkeeper is an advocate, its strange to hear that). Moreover the shopkeeper has also to "comment"that the product is used. I don't know how did he come to know that, he didn't even bother to take the product in his hand "dekh kar lag gaya unhe aisa"dont know if policy didnt allow him or his arrogance and attitude??