Please find below how to read your mail on the web, from any PC, for your accounts hosted by JSM-Hosting.
Go to http://yourdomain.ext/webmail/ or http://yourIPaddress/webmail/.
Username: "mailboxname@yourdomain.ext".
Password: the one you assigned when creating your mailbox in your cPanel.
Three web-mail management softwares are proposed - I prefer Horde and, to a lesser extent, SquirrelMail.
You can also set-up Outlook to read your email accounts hosted on JSM-Hosting - and use this webmail service to read the mail you haven't yet downloaded with Outlook.