An iPhone that's not original

I bought the device from someone believing it was an original iPhone, and unfortunately, after taking it to multiple stores, it turned out to be fake. Even though it comes with an invoice and the serial number matches the one on the device, I searched on Apple's website and found the serial number exists, but the internal components of the device are not the same as those of a genuine Apple product. If anyone wants to buy it from me and help me recover some of my loss, I'd appreciate it, as I paid for it.