Is my iPhone new or refurbished

My boyfriend bought an iPhone SE 3rd generation from china for me. I checked its model number and it starts with 3 rather than a letter (M,F, etc), plus there was no apple sticker in the box which made me question if the phone is actually new as the vender keeps telling us. I found a site where you can check the model number and there it says that the phone is « retail unit ». So I do not know if we should ask the seller to refund us or not.