In my experience the Customer Service folks are more familiar with the process. I used to go to regular registers and walk the rep thru it, but now i just head over to CS.
Strangely, and I've been using this method for quite some time so I am reasonably familiar with it, the new Target at Cabrini Green is incapable of loading my cards. The registers just don't do it. I've tried multiple times and with multiple people and always the same sad result. So I wind up going over to the West Loop Target where it works perfectly every time.
The reason I point this out is that it *is* possible that some Target locations just aren't built to handle AFT loads. If you run into that, try another Target. It may just be that location that is not working and there is nothing wrong with your card(s).