Help with Revolut discarding my chargeback

So basically, I bought an item from a Japanese proxy site, you basically bid on an item and they take it in their warehouse and they ship it to you after you pay. I did that, my package was worth 500 euros, and I chose to ship the package with surface (by ship). It took 3.5 months but eventually the item reached my country. Unfortunately the item stopped at customs and they sent it back. I contacted the site for this and they sais they cannot do anything about it and that I have to wait for it to go back and REPAY for shipping. Mind that the decleration price or the name of the item isn't something I can change, making me unable to fix this issue myself. Now, I issued a chargeback in revolut because, I will have to wait around 6 months now for the package to reach me and I have to repay shipping, and I don't even have it guaranteed that the package will reach me, it could very easily stop at customs again. I told that to Revolut and the denied my chargeback. What can I do to get my money back from revolut? I am desperate