Whenever u have an email address inside a Joomla page, it would be linked automatically.
To disable this feature, log in as administrator.
1. Goes to Mambots -> Site Mambots
2. Unpublish the Email Cloaking Mambot
Update @ 2013-05-03: Disabling the plugin ‘Content – Email Cloaking’ under plugin manager could also solve this issue as suggested by Larisa. Thanks Larisa. =D