I purchased an ebook that I'm 100% sure is in the public domain (published in 70's, no copyright notice or copyright reg with us office).

However, the company I bought the ebook from has this in their terms and agreements that I had to agree to before checking out:

"all content included on this site, such as ... digital downloads ... is the property of [company]". 

To clarify the website that I purchased the book from is the same company that originally published/ wrote the book.

So, my question: While this document is in the public domain, can I legally redistribute it, or due to the terms and agreements can I not?