One thing to ask after your headshot session if you are not happy is why?
Is it a problem of the photographer, or is it an issue you have with your own image that is out of the photographers hands.
if it is the former, then the best bet is to approach them directly and discuss why you are not happy.
A lot of issues can come after a shoot when you look back and think that you look tired as you didn't sleep all week, or your hair was too long etc, all problems that are out of the photographers hands, so preparation is the key in these circumstances.
APHP Approved also means that in the rare instance you have a problem with an APHP qualified photographer that you cannot resolve directly with them, you can contact the APHP for help in resolving.