Yes, if you are getting unwanted messages from a particular member, you can block them from contacting you again. When viewing the message in your mailbox, simply click on "block user" and they will be added to your list.
You can view all of your blocked user's or unblock them via the Blocked Users menu option.
7) How do I cancel my membership ?
Sign in and click on My Profile, then click on "Cancel Your Membership". This will remove all of your personal details from our database and is permanent. Alternatively you could select "Suspend my Profile". This will hide your profile from searches, but not delete your information and you can reactivate it later.