Buyer D agrees a contract with Supplier C which includes the words 'to be agreed'...

Buyer D agrees a contract with Supplier C which includes the words 'to be agreed' in relation to the date for delivery of the goods. At the time of the contract, Buyer D is aware that the goods take two days to produce and one day to deliver. Buyer D contacts the supplier one week later, requesting the goods be delivered the following day. Supplier C is unable to deliver the next day but rather delivers the goods three days later. Is it the case that Buyer D can legally refuse to pay for the goods because Supplier C is in breach of contract?