If you no longer wish to receive mail from a specific character, you can block it. 

■ How to Block Mail

 1. In the Received Mail list in the Personal/Guild tab, select the mail from the character you want to block.

 2. Select the Block button to the right of the sender.

 3. Enter the reason for the block and select OK.

 4. The block information can be found in the Mail > Block List tab.

※ Mail-blocked characters can be released at any time from the Mail > Block List tab.