My Mother's Last Name in Birth Certificate

[Michaelamyan 0]

I'm applying for immigrant visa for my wife in Egypt (In NVC Step now). I'm the sponsor and my mother is co-sponsor (I-864A).. I called NVC last week and they said that I didn't send a proof of relationship between me and my mother and they asked me to send a copy of my birth certificate. The problem here is that my mother's last name in my birth certificate is not there... My birth certificate has her first and middle name only.. so I didn't know what to do!!... I sent to them a copy of my birth certificate, name affidavit (my mother signed in front of notary stating that she is the same person), a copy of her old Egyptian passport showing her full name which include both middle and last name,and a copy of her American passport as well.... Should I send something else!!!... I'm so worried about that and I called NVC again today and they didn't put any in system yet (didn't review it).... and when I asked them if this is enough or should I send something else.. they said that they will review the documents first and will decide..