Password Retrieval Does Not Deliver PW

Someone hacked into my wordpress and basically tried to wipe it out. We were able to restore it to the old settings, but in the process lost our logins. I was able to retrieve a password for one of our users that lacks admin status, but for all the admin accounts, the password retrieval is not working. When I enter the correct email address, it says a new password is being sent, but it never arrives. Does anyone have any advice?
Thank you