These instructions only apply to free 100mb email accounts and 5gb corporate email accounts
From the members home area, click on the option: My domains:
Select the Domain to which you are going to create the new email account, and then click active
Click on the option Manage Mail hosting
From the mail hosting administration window, click on Manage accounts:
From this section select Delete in front of the account you wish to delete:
NOTE: Deleting an email account does not mean its cancellation, therefore your service will maintain the same price, since you can create the account again without having to buy an additional email account.