we going through this same thing. my fiancé called Uscis like a week back and they told him our case was sent to nvc, when i emailed nvc they replied that the case was received, but we haven’t got any case number yet. so today i had an online chat with one of the representative at uscis and she said our case hasn’t been sent yet as per the record. we are confused too. it’s been 60 something days since approval.., but we are trying to stay positive .