The purchaser may not approve the terms of payment of a subcontractor if the single copy or the certificate of transferability has not been amended or if the proof referred to in article R. 2193-6 has not been provided to the purchaser.
If the purchaser remains silent for twenty-one days from receipt of the documents mentioned in the first paragraph and in article R. 2393-27, this also constitutes acceptance of the subcontractor and approval of the terms of payment.