Interview Scheduling Issue

[Guigui&Arlee 6]

My fiance recently payed the k1 visa fee and tried to schedule an appointment. The embassy in France gave us the interview date, which is March 3rd, but when he went to select that day it wasn't available. So he chose the 10th thinking that's what he had to choose. He called a number on the website and they told him to email the embassy which he did. All the embassy told him was he had an interview date on March 3rd. They didn't even answer the question, so he emailed them again and they said the same thing word for word. Does it matter if he can't choose the right date? We have no idea who else to contact. Thank you.

[Guigui&Arlee 6]

No one knows? His interview is in about a week so we are getting concerned.