Does a spell getting Defy's count towards Battering Ram reduce cost?

No, a spell that gets countered (defied) does not count toward the cost reduction of Battering Ram.

According to Rule 425.1.b: "A card that is Countered is not considered to have been played."

Because the spell never finishes the process of being played, it does not count toward conditions that check if you have played a certain number of cards that turn. Therefore, it will not trigger the cost reduction ability of Battering Ram.