I am sorry to hear about the various difficulties you refer to with listing at this time. Unfortunately, to be able to assist you most effectively, our support team would need to have a look in your account at the affected listings and the responses from eBay.
We are unable to speak to when Managed Payments may be available in Australia, but we are aware of the roll out eBay has planned for this in general terms and most listings can still post to eBay without difficulty and the set up for managed payments is being added on the eBay end at this time. We expect to have our listing creation page updated in the near future.
Please feel free to file a support case from under the Help tab of the site or using the Support icon that is available on most of the site pages and please include specific examples by title of listings that are running into the issues you refer to and our agents will be happy to take a look. Please keep in mind that at this time we are experiencing a heavier than usual support load and are still operating with the various difficulties associated with Covid-19, so our response time is less rapid than usual. Apologies for any difficulty that may cause.