I had similar situation. NVC lost my files. USCIS resent them after 7 months of delays. I kept calling and requesting expedite, but NVC will not do anything until at least the case number is issued. It took exactly 8 weeks for them to issue me a case number. It is an automated process, so to be honest, there is nothing you can do until the 8 weeks have passed. You should get the case number soon though. After that, you can request the case to be expedited, but again, it won't happen.
You need to speak to a supervisor on the phone and then you need to request an expedite on the basis that USCIS and NVC are at fault for lengthy delays and errors. With complicated issue talking on the phone with the supervisor is a better first route than an email. Also you can contact your local representative.
