4.2 The commission and any reimburs

4.2 The commission and any reimbursement shall be invoiced by XX by the end of each calendar month, the invoice being separate from the invoice issued by the suppliers. Each invoiced amount will be entered into a clearing account and shall be paid by HSE24 by the end of the following month in the course of clearing. Should HSE24 be in default, the statutory provisions shall apply. However, a written reminder (Mahnung) by XX shall be required in any event.