Hi there,
You can order your CAIPs notes to get an idea why they think you require an interview. If they dont think that the marriage is genuine, then you can send more relationship proofs to show that you guys are in a continuous relationship. The people over at the Islamabad thread do this all the time because they have a longer processing time, and there were even instances when the interview was waived!!
So I believe, the first thing you do is order CAIPs/GCMS notes to figure out why you guys might require an interview. Which VO are you applying from though?
All the best!