Unwanted Email Notifications for all testers on defect creation, status or any change or comment in the defect

Hi team,

Could you please guide me on the email notification issue. Email notifications are being sent out to all testers if any tester creates or make changes or assigned to other tester. All the testers are getting email notification for the defects of modules not related to them. For time being, I have turned it off. Email notification is expected only to the user who is owner of the defect and username in the detected by field. We have now UAT phase and need this functionality at very urgent basis. Can anyone help. I have dropped email to the support team but don't know how to contact them.

Please guide me on this major issue.

Thanks,

Manju