This is exactly the type of situation that I hope to avoid by shopping at Eden. If I ever have a problem with anything, customer service (Antoneo) has been wonderful in addressing it! That said...
You CAN get your money back for a knock off! Amazon DOES refund or replace faulty items, even sex toys! They just don't accept returns, get it? I have seen so many people give up because Amazon lets them misinterpret that no returns stuff. When you buy something, you have the reasonable expectation that it will work, not that you like it, just that it works. If you received something broken, you contact the seller through the Amazon system and if they don't make it right, Amazon will.
Since you were sold a knock off unknowingly, this is a big problem for Amazon's reputation! It might have been a while, but legally, you have from the time you were first made aware of the problem to seek satisfaction. If you used a credit card, you can have that backing you as well, if need be. I highly
suggest you go to your Amazon orders page and go through there to contact Amazon (NOT the shady vendor - assuming it's not them), stating what you have just discovered! See what they suggest. Tell them you checked with Jopen when things went haywire and you compared the specs and there are no older versions, etc.
If they give you any lip, you get tough with them saying you are going to expose them for knowingly keeping quiet about and refusing to do anything to rectify the fact that they sold a knock off Jopen Intensity! Then tell them you are contacting Jopen about it too! However, I don't think you will have any problem, Amazon and any vendors I've worked with there have been prompt to remedy any situation. Please let us know what happens!