Managed to get my miles back by:
1. Emailing to the Lifemiles support ID, informing them of what had transpired.
2. Lifemiles noted that they did not have a record of this ticket being cancelled and asked me to forward them the CC statement.
3. Emailed a PDF copy of the CC statement and the authorisation number.
4. Miles refunded within 24hours.
Maybe you'll have to do the same as well.