I really wished the person said it didn't come with a jacket so I wouldn't have picked this persons book. What can I do now?

Hardcovers do not have to include dust jackets, nor do senders have to notify you if their book does not have one. If you wish to only receive hardcovers with dust jackets, I'd suggest creating a requestor condition for it.  It's really the only thing you can do to ensure you get books in the condition you want them in (beyond basic postability guidelines). 

thanks so much for the idea

Nope, not an issue at all.  The posting guidelines clearly say hardcovers do not have to have dustjackets.  Sender does not have to let you know this beforehand.

Lots of people like dustjackets though.  You've got to do that Requestor Condition if you want them on every hardcover.