i have over 450 users..when i change to another isp the users connect to router,when the electricity off
most of users not connected until the customer turn off the router then on or connect manually.
plz explain why?

You have to tell some more about your setup. Hotspot? pppoe? dhcp? how do the customer connect? what happen after the box they connecto to. It seems like you like to give them a new gateway? (trough new isp) is it static route? or dynamic?)