amie,
Even well trained and very experienced shoppers have failed shops every now and then. I think that if you are getting repeat requests from the same MMSCs to do video, you are doing well. Instead of adding a training couse aimed at rookies, if I were you, I would call a couple of your schedulers and ask them for feedback on what skills they wish that you would polish.
BTW, I hope you, at least, got paid a "trip charge" for going to meet the uncooperative target. If he just flat out refused to make an appointment, that's not a failed shop in my book. If he made an appointment, you arrived and have him on camera refusing to proceed, you should get a trip charge, at least, and probably should have been paid for a full shop, since the target, not you, "failed" in tht case.
Based in MD, near DC
Shopping from the Carolinas to New York
Have video cam; will travel
Poor customer service? Don't get mad; get video.