Unload Benefit Cards

Unload money from a batch of benefit cards. Provide a list of cards and individual amounts to be unloaded from each card. If all pre-conditions are fulfilled, then the request is accepted and processed asynchronously. Listen for appropriate CARD_BALANCE_UPDATED callbacks. If any of the pre-conditions is not fulfilled, the request will be rejected immediately. All cards have to be eligible for card unloading, i.e. they are active benefit cards and belong to the same organization. All requested amounts must be positive, specified in the card-account's currency, and must not exceed the individual card's available balance. There must not be any pending unload already in progress for the affected cards.