Trying to return an imitation LV

[miamigear]

So I bought a crossbody Louis Vuitton bag from Japan.  When I receive the bag the date code it’s not authentic. The seller says they can’t send me a shipping label. I have gone to the post office and they keep telling me I need to fill out some paperwork in order to ship back. I have never had to ship to Japan before so I’m not quite sure how this works. Any advice would be great. As I do not want to get stuck with this bag. They had it described as being authentic and it is not I had it checked out with my own money so I lost more on the purchase. Any feedback would be very much appreciated. I work very hard for my money 😞