This question does not to the verses Christ claims for himself the "I AM". (e.g. John 8:58)
Rather, the Jehovah's Witnesses claim He used the actual Divine Name "Yahweh" (or the faulty "Jehovah" as they say). To support this, they cite verses such as St John 17:6, 26, which read:
I have made thy name known to the men whom thou hast entrusted to me, chosen out of the world. They belonged to thee, and have become mine through thy gift, and they have kept true to thy word. ...] I have revealed, and will reveal, thy name to them; so that the love thou hast bestowed upon me may dwell in them, and I, too, may dwell in them. (Douay-Rheims)
Or in their "translation":
“I have made your name known to them [Jesus’ disciples] and will make it known. “In order that the love with which you [God] loved me may be in them and I in union with them.” (New World Translation)
They also claim that God wants us to use His Name, using verses such as Isaiah 12:4 in support.
The question, therefore, is this: Is their point correct? If not, how does one refute it?