"I am getting unwanted mails in my Inbox. How can these mails be stopped?"
While in Inbox: Select the unwanted mail(s) and click the 'This is spam' button to send them to the Junk Mail folder. The sender of the mail(s) will be automatically added to our list of suspected spammers and blocked from sending you any further mail.
While reading mail: Also when you are reading an email in your Inbox, when you click on the 'This is Spam', the email is identified as Spam and you are given the option to 'Report this as Spam' and/or Block the Sender. It is recommended that you do both. 'Block This Sender' results in stopping any future emails from this sender to your account.
'Report This as Spam' informs the Rediffmail auto-spam system that you would like this email to be treated as spam. The auto-spam system takes reports like these from you and other Rediffmail users and tries to minimize all incoming spam mails.
In My Settings: You can filter all emails and receive emails only from those in your Address Book only, on the Mail Filter page in 'My Settings'. Or you can create your own email filter and divert the imcoming emails into specific folders. To Create/Edit Mail Filters click on 'Mail filter'. Then click on the 'Create New Filter' button.