disabling users on non payment

Hi all, I would like to deactivate the users(not allowing them to login but not deleting them) on failure to pay the subscription fee. What the best and right way to do this? Also I would like to send some message why they are not allowed to login. -- Randeep Mob: +919447831699[kerala] Mob: +919880050349[B'lore] http://twitter.com/Randeeppr http://in.linkedin.com/in/randeeppr [image: --] Randeep Raman [image: http://]about.me/Randeeppr <http://about.me/Randeeppr>