This is not a tech support issue, its a customer service question:

Background:

My Aurora ACT1250 developed an electrical buzz/hum noise
Remote Tech support have been very good (although they insist its a noisy fan, it isnt)
They can't send me a video of an Aurora not making the noise so I am unable to confirm that it's normal either.

On Site support hasn't been good (the first scheduled call out was a no show, second didn't diagnose or fix the problem)

So my NON TECH support question is...

They cannot diagnose or properly repair it if they don't have access to a model to compare it to.  So, how do I arrange a replacement for a fault that cannot be diagnosed or repaired?