dont go into the centrelink office!!! it's not going to get you the time and attention you appear to need at the moment to clarify your situation

as LS said, Austudy is administered by centrelink and would replace your PPP - but you have to check with the Youth and Students area whether you are eligible based on previous study and qualifications as well as your current intended course of study. You may not be covered for both the diploma AND the uni study so check with the Youth and Students Team 132490. you may find it's better to stay on ppp while you do the diploma and move to austudy for the uni side of things, provided you don't have previous uni qualifications - definitely check with Youth and Students before you make any decisions. Austudy is a taxable income, the same as parenting payment or newstart. you cannot have parenting payment and Austudy at the same time

Fee HELP is different. it is a loan from the commonwealth. you do have to pay it back when you meet the threshold income (currently about 49k as mentioned above) - depending on your annual income, the percentage of your income you have to pay against the loan varies - minimum is 2%. the loan is also indexed every 12 months so it gets higher every year if you're not repaying it.