Need Advice on Returning a Headset to PCCG

So I bought an Aerocool Templarius Excelsus Headset off PC Case gear in April. The mic starting dying a week ago so I sent them a warranty request.

There's a crack in the plastic between the mic socket and the cable - http://imgur.com/JbrJkcb. I think there might have been a much smaller crack when it arrived in the post but I don't have any proof because I am an idiot.

This is what their costumer support sent me:

We have contacted our distributors in relation to your Aerocool Templarius Excelsus Headset. Unfortunately as there is physical damage on the unit, both our distributor and Aerocool directly have said that due to the damage on this unit they are unable to process this under warranty. As such we are unable to approve this return under warranty.

I tried quoting a bit of the ACL at them:

Hi Callum,

Under Australian Consumer Law you (the retailer) is obligated to repair, replace or refund goods which aren't of acceptable quality. This consumer guarantee applies in addition to any warranties your store may provide.

Acceptable quality is defined in section 54(2) of the ACL such that goods are of acceptable quality if they are:
• fit for all the purposes for which goods of that kind are commonly supplied;
• acceptable in appearance and finish;
• free from defects;
• safe; and
• durable.

The test for acceptable quality is what a reasonable consumer acquainted with the goods would find acceptable. I bought this headset on April 15th. The microphone stopped working on the 4th of June after a month of ordinary use. This is not acceptable durability for a headset which I would expect to last at least a year.

The superficial damage to the plastic in this case is a sign of poor build quality and unacceptable durability. Clearly ordinary use should not void the consumer guarantees required under ACL. The limitations in s262 concerning damage clearly do not apply to damage that occurred during ordinary use. Otherwise it would be impossible for consumers to get a remedy for products of unacceptable durability - which is an absurd situation.

This is their reply:

After discussing your issue with Aerocool we have been able to cover this return for you in this once off occasion out of good faith to help you out. Please be advised that in the future any units that are physically damaged will be rejected and we will not be able to accept these back as a return. Your RA will be approved shortly.

Kind of makes me wonder if they ever contacted Aerocool. I think Aerocool is a Taiwanese company and I have no idea who their nameless distributor is so I reckon PCCG is my best chance at getting a replacement. Did I actually void the warranty or are they just feeding me some bullshit?