Contact details are stored in several places and you should ensure all are kept up to date. These are
The client center.
The client center stores you client profile. Your client profile controls notifications such as purchase, billing and payment notifications, overdue payment reminders and help desk and support replies.
To change your client profile please see http://support.hostcenter.co.nz/index.php?act=article&code=view&id=302
The domain manager
The domain manager controls notifications regarding domain name related transactions for any domain in your domain account such as when you process a domain name registration or renewals.
To change your domain manager contact information please see http://support.hostcenter.co.nz/index.php?act=article&code=view&id=304
Domain name contact information
Domain name contact information controls domain name notifications relating to an individual domain such as renewal reminders and registration cancellation warnings. It also controls the email address a domain names UDAI will be sent to when requested.
To change your domain name contact information please see http://support.hostcenter.co.nz/index.php?act=article&code=view&id=49
Web hosting control panel contact information
Web hosting control panel contact information controls notifications about your web hosting account such as low disk-space and high data transfer warnings
To change your Web hosting control panel contact information please see http://support.hostcenter.co.nz/index.php?act=article&code=view&id=305