You mentioned Cpanel, so if your site is offering that, you should be able to login to the CPanel and access mail through that. FTP won't help much for email, but there is a possibility to get the *raw* mail from certain locations if you know what you're looking for. BUT, it's likely going to be far easier to get it from CPanel and utilize the email account features there. You might also check your Outlook POP access details to see that you're using the right configuration to POP the mail. If you get that working maybe you can download it. A 26mb file is going to take a WHILE on dialup, and even a bit on other access formats, so the timeout issue mentioned above could play a part too. I'd have to make sure to use a download manager to download something that huge, so as not to "drop" it.
Anyway...try getting to your mail via the web access of your CPanel and see if you can find your mail there. You should be able to click on the "manage accounts" or whatever to see what emails are setup for one. then from that page you should be able to click on "read webmail". Settings for Outlook and that are available there too. If you click on "read webmail", you should be able to access mail for whatever account you clicked on.