Bought a bad quality laptop online and hi store doesn’t want to help

I’m not happy with Hi store policies especially when you sell a bad product to a customer. I lost a box of a brand new laptop, granted I’m wrong for that, but it can’t be that there’s nothing a store can do about that, whether it’s charging me for the box or something. Anyone can see that the information on the box is pasted stickers, surely it exists somewhere in the system so the whole thing that you can’t help a customer because they lost the box is totally unfair. I trusted that the laptop was good and I started using it until I discovered it was too slow - why are you even selling that for a high price and call it normal? You must understand that your customer doesn’t know your product and the specs it provides, they are trusting you to sell us quality, why are you punishing us for buying a bad product from you and not meet us halfway.