Accounting for proceeds from fulfillment company

[slicksmith]

We have begun using a fulfillment company (FC) to take and ship orders. In most circumstances, they receive credit card payment at the time of the order using their merchant account. Each day we receive a shipping log list from them, and create an invoice in QBs for the amount of the order. At the end of each week, the FC sends us a check for the sale proceeds minus their expenses for shipping and their service fee. Because the FC is taking payment in full from the customer at the time of the order, when we create the invoice, we also receive the payment so the invoice represents that it is paid, and select "Group With Other Undeposited Funds" because these credit card payment are not on our merchant account, so don't go directly into our bank. Our dilemma is how to actually make the deposit for these funds once we receive the check from the FC because it is a net amount, rather than the full amount of each customer's payment. We know that the deposit needs to split between the customer payment, shipping expense and FC Services Expense, but are at a loss as to how to do this. It would be easier if the FC would remit the gross proceeds which would correspond to the total Undeposited Funds amount, and then allow us to pay them for the shipping and service charges separately, but they will not. Anyone have a suggestion?