Always be respectful and treat your matches as you would want them to treat you. Not every match is going to be right for you so closing communication with matches and having matches close communication with you is a natural and healthy part of the process. eHarmony is about bringing two compatible people together who have a solid foundation from which a long-term relationship would have a high probability of success. You still need to carefully consider whether this particular person is one with whom you would like to further a relationship. If you feel the need to end communication, then be honest, direct and polite. The sooner you address this determination, the better for both of you.
If a match feels the need to close communication with you, please respect their wishes.