I had problems with him as well, see this thread:
http://www.net54baseball.com/showthread.php?t=178809
Fortunately the deal eventually got done and the 1964 Topps Giants Ken Boyer auto passed 3rd party authentication (not to say that means it is 100% guaranteed authentic).
I feel bad for anyone that got screwed by this guy, but at least he won't be able to do it anymore thanks to Leon and some concerned board members.