According to EU Consumer Rights, a 14-day Cooling-off period is present .

Notwithstanding the above, if the merchandise is being shipped into the European Union, you have the right to cancel or return your order within 14 days, for any reason and without a justification. (Preferably before the actual fulfilment) As above, your item must be in the same condition that you received it, unworn or unused, with tags, and in its original packaging. You’ll also need the receipt or proof of purchase. Extra note: Withdrawal is not possible for custom and personalised orders.

To comply with the consumer rights every online store must have a withdrawal submission form. So here it is.