It is because the terms are in a definite form capable of being accepted in identical terms. An agreement comes into existence after the offered unconditionally accepts the offer”. On the second day, Ben accepted Dad’s offer and an agreement has been made as Ben replied Dad “Sure” by vocalism. As Dad did not clearly indicate the method of acceptance, the instantaneous vocalism message left by Ben is counted as a valid method.
However, as the postal rule does not apply to situations where the acceptance of an offer is communicated by any instantaneous methods, the contract is complete only when the acceptance is received by the offer in such methods. In Entrees Ltd v miles Far East Corp., a interact was made between the parties only when the offers acceptance was received by the offer. Therefore, as Ben used vocalism, which is also a kind of instantaneous means, as an acceptance method, a valid contract will only be made when Dad received and listened to Ben’s vocalism.
So no contract was made in this stage yet. However, Ben then changed his mind and sent a letter of revocation to Dad. The significant part then appeared. Although Ben sent a vocalism message to accept Dad’s offer first, and posted a revocation letter to Dad afterwards, the letter reached Dad earlier than the vocalism. According to the general rule, the revocation of an offer becomes binding when It comes to the knowledge of the offered and an offer can be revoked at any time before Its acceptance.
And at the moment Dad received Ben’s revocation letter, she still have not received Ben’s vocalism acceptance. As I analyzed before, for Instantaneous methods, the contract Is only complete when the acceptance received It, not based on the moment of sending. Ben’s revocation has already become effective when It reached Dad and the contract was not completed. Hence, no valid contract was made between them.
