https://www.leupay.eu/en/legalClient agrees that iPay may not be always able to reverse the amount of unauthorized transaction or incorrect payment order, in cases, where the deadlines for chargeback or reversal procedures before the Card Organizations have expired or in other cases according to the rules of the respective Card Organization, in which cases iPay shall not owe Reversal or compensation to Client.
This sound more like paypal chargebacks, so you better deal with only trusted buyers with high number of positive feedbacks.