Hi DrD,
Before we start processing the issue, I would like to confirm some information:
1. What do you mean by saying “get app from store”? Is it the store in Windows 8 or app store on the mobile phone?
2. Is the email address an Office 365 account, an Outlook.com account or etc?
3. If it is an Office 365 account, can this account receive emails from other email address such as Outlook.com, Gmail?
According to the detailed information, I would try to reproduce the issue which you encountered.
Best Regards,
Bruce Zhou