Sorry to hear about that Rachel. I am not aware of NDVOs timeframe. But 6months seems a little long. Typically email/fax enquiries receive a prompt response. I wish you the best. Worst case, maybe you could contact them directly (in-person) or have a lawyer do the same on your behalf.
You can also pose this question to some of the seniors on the forum. I am sure they have more insight into such matters.
SF2005