Answer: Please register your complaint here. It is important that you fill in all the columns carefully. 

If the defect is not covered by the guarantees of the right to make a complaint, we have the right to not accept the complaint.

You can read here about guarantees here. 

Does it apply to leather?
Keep in mind that leather is a natural material which means that it always has more or less structure in its appearance. Differences in structure and appearance in a leather product are not to be regarded as a defect and thus not as a reason for replacement or complaint. Remember that horses are big animals and if the leather is put under a lot of pressure it will break no matter how good the quality is. 

Does it apply to pearls, crystals, rivets and other decoration ?
For example on headbands is only for decoration. This decoration is fragile and if the decoration breaks, this can not be considered a defect in the product and can not be complained about.