Disappearing books and downloading videos

[Firstname]

I purchased 5 books from google about 10 months ago and now they are gone from my tablet.  I also checked my google play account and they are not there.  What happened to them after I sent google the money so you would think I would own them and not have them disappear. 
I also tried to download a video from a web page.  It said it downloaded but could not find it.  I did find the name in "downloads" but there was no way to play them. 
Any ideas as to these problems
Still very disappointed in the nexus.

[Tiny]

Have you asked Google support about your books?

Contrary to popular belief digital books, music, movies, etc. are different than physical books, CDs, DVDs, etc.  You do not own them, but have purchased the right to play them.  If you had a hard copy book, you could sell it or leave it to an heir.  You cannot do the same with a digital book.

Based on the information in your question, it is hard to guess about your video download problem.  I would guess that you probably to not have a compatible video player installed.