You can return goods to seller in exchange for other goods according to the “Consumer protection law”. The return of goods, even if it is not defective goods, is possible only in case when its integrity is maintained (product itself, packaging, seal, label) and accompanied by a sales document, confirming the purchase of the product in question and also by buyer’s identity document.
In the mail you should specify the order number, attach a copy of the buyer’s identity document and explain the problem in detail.