Sending, receiving, and organizing email in Outlook.com
It sounds like your Outlook account may have an incorrect display name saved somewhere. Try checking your Microsoft account profile at https://account.microsoft.com/profile and make sure your name is correct. If it already shows your correct name, check your Outlook settings under Settings > Account > Your info as well. You can also try sending an email to a different address to see if the same name appears.
If the name is still showing as Joseph Atzinger, it may be an account or profile sync issue, so contacting Microsoft Support would be the next step.