Inadequate foot in length. see photo 18/19 cm

Hello, Magré ad 45/46 XL or the foot of the sock measuring 18/19 cm at rest, while my foot measures 25cm,
despite the fact stretch "stretch" impossible to get the required length, so the foot is too small, a pity because the product is superb,
Material and color, but I do not have the possibility to use it;
What is needed to return or find a buyer "Had hoc"
With my compliments. PK