Hello, ,
Yes, If you cancel the subscription your email address will remain the same (i.e. @msn.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.
Since you have DSL connection you can continue with MSN Premium Subscription and cancel MSN Dial up service.
Please contact Microsoft Billing support team to get help on this issue.
Please check the private message for MSN Billing number to get assistance
Note : Please sign in with your MSN email address and password to check the private message
Thanks
Jason