Hi,
No, If you cancel the subscription your email address will remain the same (i.e. @msn.com,@live.com, @Hotmail.com or @outlook.com ) also you can access the emails through https://www.Outlook.com.
Your email capacity will get reduced from 10 GB to 5 GB.
Users will get notification email if your storage capacity is close to full.
Thank and regards
Jason