Oh My Goodness! review for FreshCredit ‑ Store Credit

I don't mean to leave a review but I couldn't find another way to ask a question. I set up FreshCredit as per the video, walked my customer through the steps as per the video and his credit didn't show up in check out and he got fed up and just ended up paying which was rather embarassing. Could you pls help me figure out/fix what went wrong pls?