@markem; thank you for the information! I have sent the local office of Dupont a mail with photos and the information i already provided to you guys, and am now waiting for their reaction.
@wharf rat: don't worry, i have read about Duponts refill canisters

With wheel i meant the thing on the side of the lighter that you have to turn, i'm sorry i don't know the correct name (english is not my first languague)
@mosesbotbol: i have tried resizing the pictures. The color inside the o-ring is yellow/gold like. May i ask you; why is it certain that it leaks? How do they make 500 euro + lighters and people accept that they will leak

?
thanks for your reactions so far people, they are really helping!