To block a friend from exchanging messages with you, tap the
friend in the chatting list. Tap the Menu key > People & options. Tap the block option, then tap
the Block button to confirm.
To remove a friend from the blocked list, tap the Menu key from the chatting list. Tap Settings > tap your account > Blocked people > Unblock next to the person’s name.
Once you block a friend, all of your chats with that friend are deleted from the chatting list.