Can't access lesson files

I went to Peachpit Press. I entered the ISPN number. It didn't work. I rechecked and retyped at least 3 times. It is a brand new book. Still no luck. I contacted support. They wrote back that I needed to send a proof of purchase. I sent the Amazon order number and link. They seemed to be satisfied with that and said they had moved my case up to the next level.  I have given up waiting on them. I can go through the book and benefit from it without the files but I would rather have them. Where would people who bought the book used go to get files? The unofficial page? I certainly cannot be the only person who had this problem.