I ported my number out to Telstra to save money because $70 for 7GB was ridiculous where I could get 20GB for $49, anyway, I understand that I need to pay out the rest of my plan and I am more than okay to do that. $615 has been direct debited from my account which is now -$611. I can't pay my bills, my rent, my finance or feed my cat let alone myself. What are the chances of Optus putting the money back and me continuing to pay month to month?
I'm afraid billing is handled automatically so when your number was ported out. The account was closed and your cancellation fee was published. Your previous invoice contains the fee along with any upcoming payments on the first page. You would need to cancel the direct debit before this date, although leaving it unpaid would mean being referred to a debt collection agency.
To issue a refund, your account would need to be in credit but in these circumstances your balance is going to be $0 and a final invoice should be sent soon.
I'm afraid to say it would just be too late at this stage. Any payment plans etc would need to be organised before the due date of your final payment.