The BigPond mail servers automatically removes approximately 98% of all spam. This may still leave a large number of emails that reach your inbox.
Spammers adapt to the changes in spam filtering and continually work around filters set up on mail servers and security software. They also have methods of concealing or spoofing their email address which can prevent spam filters from performing as expected.
We are aware of an issue with the limit on the number of email addresses that can be blocked. In the interim, you can go to Settings > Organise Inbox and configure rules which will allow you to delete emails with specific words in the subject or from a specific email address.
I understand that this is not an ideal work around, but should help you in the interim.
Another thing to consider is how the spam is generated in the first place. Typically this is by allowing social media platforms such as Facebook etc to publicly display your email address, by clicking on phishing links, virus activity on your computer as well as some websites where you have registered your email address may sell that information to a 3rd party.
You can also report spam via http://www.acma.gov.au/Citizen/Stay-protected/My-online-world/Spam/reporting-spam-i-acma
- Shelly