Extracted from your contract:
10.1 The Independent Contractor is responsible for all taxes and levies relating to, or in connection with, the provision of the Services by the Independent Contractor to the Engager, including but not limited to any income taxation payments, GST payments or superannuation payments required under the relevant legislation.
11.1 The Independent Contractor acknowledges and agrees that the Engager is not the employer of the Independent Contractor or any person employed or engaged by the Independent Contractor to perform the services. The Independent Contractor acknowledges and agrees that the Engager may, as part of this Agreement, be required by law (including the Superannuation Guarantee (Administration) Act 1992), to withhold from any amount owing or payable to the Independent Contractor any amount that may be required by law to be paid into a complying superannuation account in satisfaction of the minimum superannuation guarantee contribution.