Section 15. Liability of buyer to make payment.

Where any supplier supplies any goods or renders any services to any buyer, the buyer shall make payment therefor on or before the date agreed upon between him and the supplier in writing or, where there is no agreement in this behalf, before the appointed day: Provided that in no case the period agreed upon between the supplier and the buyer in writing shall exceed forty-five days from the day of acceptance or the day of deemed acceptance.