The Torah states (Bereshis 35:10) that when G-d blessed Ya'akov, he says, "Your name shall no longer be called Ya'akov, but Yisra'el shall be your name". If so, why does God, and we are allowed to call him Ya'akov, whereas, we are not allowed to use the names "Avram" and "Sarai"?
According to the Gemara, the verse is saying that his name is no longer only Yaakov.
As far as to why he is different than Avraham, the Gemara further states:
Hashem himself subsequently called him Yaakov.