I have developed CMS for captive portal , allow you to manage your wifi ,
add new users
control with user's properties (session time out , quota , bandwidth, expiration time , login time ...etc)
view logs (start date, stop date ,download MB, upload MB, mac address , ip address , system ),
send email message
send sms message
charts
voucher
backup
administration config
customize login page ,
customize voucher design
I can give you this system or create new CMS for you with just users management and logs , but of course price different