I asked them (by email) and got an answer that they scan 4x4 negs, but only color negatives.
I replied that that's ok for me. My b&w negs can be scanned as color negs. They did not reply. Maybe they have customers more than they can handle...
If they haven't done it before they may be reluctant to engage the time needed to make sure they can satisfy the customer with adequate quality, which really should be very easy given the materials they are using. That said, it's really poor business practice not to answer email inquiries from prospective customers. Given the good reputation they have, this may be an oversight. In your position I would forward them the email with a reminder that you expect a reply from them.
