To re-download your Office 2013 product you will go to www.office.com/myaccount and log into the Microsoft account you initially tied the license key to. If you do not remember your Microsoft Account to re-download your product you will have to purchase a new product key.
Microsoft will not provide account information to you. If you would like to try to contact Microsoft please call 800-642-7676. SoftwareMedia does not have any access to Microsoft accounts and is not able to assist in recovering this information.