A drywall subcontractor named Jack Munster performed work for Ace Contractors, a general contractor. The value of the work was $1,500. When he did not receive payment, Munster sent a letter threatening a lawsuit if prompt payment was not made. Soon thereafter, Ace Contractors sent a load of drywall to Munsters business address. This material, which was labeled as being in fulfillment of the debt, was accepted without protest. Six months later, Munster sued Ace for $600, the balance that he had determined remained on the debt. Discuss the strength of Munsters case from the standpoint of consideration.