I am looking to start a new phd. I was a dietitian in my country and moved to australia two years back. i have been looking for supervisors, struggled to find one, got no reply for my dozens of emails and was frustrated when an Ass.prof called me and told that he could help me finding one and also gave me a new supervisor's contact who's never had a student before. I was happy that i even got one to support me and started wotking together. finalised a topic and in a jiffy a year passed by and i found that i am still not a student of the uni and i am still working on the topic which needs refining and the proposal has to be corrected again. At this stage, the new supervisor says me that the current topic i have is not feasible and cant be taken for a phd study and it needs more participants for an RCT and its time consuming. Now, I have to look for a new topic from the scratch!! What should i do? should i change my supervisor or where am i going wrong?

If you're not a registered PhD student, you don't have a supervisor...

Can't you apply for advertised projects, that will assign you a proper supervisor?