Take them back to the retailer and get them sort it out. Under the Australian Consumer Law, it's your choice as to whether you contact the manufacturer (or distributor) or retailer over warranty issues. If you feel you're not getting anywhere with one, try the other. It's disappointing they haven't been helpful.
Speaking of the Australian Consumer Law, find the relevant bit and start quoting it to them. That usually moves things along.
Repair, replacement or refund
You can ask a business for your preference of a free repair, replacement or refund, but you are not always entitled to one. For example, the consumer guarantees do not apply if you got what you asked for but simply changed your mind, found it cheaper somewhere else, decided you did not like the purchase or had no use for it.
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If you have a minor problem with a product or service, the business can choose to give you a free repair instead of a replacement or refund. When you have a major problem with a product, you have the right to ask for your choice of a replacement or refund. For a major problem with a service, you can choose to receive compensation for the drop in value below the price paid, or a refund.
I
Crazy keen tramper / trekker / hiker. Former South Australian. Now, exploring the tracks around Melbourne and Victoria.