If the email addresses are linked to an ADSL service that will be cancelled then you will lose the email addresses unless you sign-up for the paid email service.
It's $79 per year, per email address you want to keep active.
You can find the info at https://www.telstra.com.au/content/dam/tcom/personal/help/pdf/cis-personal/broadband/personal-critical-information-summary-paid-email.pdf
Until it gets cancelled though the email settings you need can be found at http://support.telstra.com.au/t5/Set-Up/BigPond-settings-for-POP-IMAP-and-SMTP/ta-p/398464
It's $79 per year, per email address you want to keep active.
You can find the info at https://www.telstra.com.au/content/dam/tcom/personal/help/pdf/cis-personal/broadband/personal-critical-information-summary-paid-email.pdf
Until it gets cancelled though the email settings you need can be found at http://support.telstra.com.au/t5/Set-Up/BigPond-settings-for-POP-IMAP-and-SMTP/ta-p/398464