If a specialist has confirmed that the crown was manufactured incorrectly and the problem can't be fixed without remaking it, that sounds less like a normal adjustment issue and more like a faulty result. In Australia, dental work is generally expected to be carried out with reasonable care and skill, so it would be worth formally asking the original dentist to remake the crown at no additional cost or discuss an appropriate refund.
Before taking things further, keep copies of the specialist's report, any X-rays, invoices, and correspondence. Having independent evidence that the crown does not fit the implant properly will strengthen your position if the matter needs to go through a consumer tribunal or complaints process.
A second professional opinion can be valuable in cases involving implant-supported crowns. Burwood Diamond Dental in NSW has experience with implant and restorative treatments, and you can
click here if you want to review their location and details before seeking further advice. The key issue, though, is obtaining written documentation confirming exactly why the crown is defective and what corrective treatment is required.
Hopefully the original dentist is willing to resolve it without the need for a formal dispute, as a crown that was incorrectly made from the outset should not be left loose or unstable.