The return costs are fixed because we have one warehouse in the Netherlands from which we ship from and receive returns worldwide. For a company our size and the freight charges we face it's simply not sustainable for us to offer this as a free option and compete on these terms with companies such as Zalando and Amazon.
If by any chance you know of a cheaper way to send it back on your own initiative just let us know and we will send you the details.
We can only hope for your understanding on this point.