Hans,
Familiarise yourself with the contents of this page:
https://www.accc.gov.au/consumers/co...replace-refund
3 months seems more than sufficient time to decide if they can repair it & actually conduct the repair IMHO..
I would go back in, armed with this information & press your case...
To be honest, I never bother with extended warranties... you are basically paying for something that the Australian Consumer Guarantee covers anyway in that 'a product should last a reasonable amount of time'. What is considered reasonably does vary but, largely comes down to how much you paid for something... ie: a TV costing a couple of thousand should last considerably longer than the 2, maybe 3 year warranty it comes with. We have had many successes pressing our claims on products that have been as old as 5 years but, only had a 1 year warranty on the basis that for what it cost, it should last longer than it did. In no cases did we actually have to involve the ACCC, simply a mention of Australian consumer law & being firm, standing your ground was sufficient.
Sorry to hear of your printer woes, we've had an eco tank for about 7 years now, works like a charm & has saved us a fortune on the all in one printer cartridges...
Hope the above helps
Cheers