Where an arbitration clause limits recourse to the ordinary court to invoices relating to goods received without dispute, the burden lies on the party invoking arbitral jurisdiction to prove that the invoices subject to the payment order relate to supplies that were actually disputed, it not being sufficient to produce generic communications of non-performance that do not allow specific identification of the disputed supplies.
An arbitration clause that expressly reserves to the ordinary court jurisdiction over payment of invoices does not preclude the exercise of state jurisdiction for the recovery of commercial debts, regardless of the existence of any disputes concerning the supplies.