Protecting Myself for a T-Dimension Warranty Claim

Hi all,

I recently purchased a OnePlus 8 Pro through T-Dimension after weighing the pros and cons. My 3 phones since 2014 have been grey imports as well and never had any issues so I took a bet and went down this lane. The device arrived relatively quickly and Iw as pretty satisfied with their order fulfillment.

Unfortunately the phone arrived with a known issue plaguing the device. The panel exhibits a non uniform "green tint" at low brightnesses on screens that are grey in colour. I contacted them with relevant photos (https://photos.app.goo.gl/M8tLDrUqVLaSTMuC6). At first they said it was normal and I had to follow up with more evidence showing that it is indeed not normal to have green showing on part of the screen when the entire screen should be a uniform grey. They then responded saying they would accept the device back for checking, but if they find out that it isn't a manufacturer's defect I will be charged for the postage to and back from HongKong. I have reached out to another ozB user here who has purchased the same device from them and he has very generously provided photos of his phone which doesn't have this issue so I have enough to show that it isn't normal.

So right now I'm at an impasse, while it is a known issue, the manufacturer OnePlus has never formally claimed it as a physical defect but more of a software issue (I am currently on the latest update and while it has been fixed for many people mine still has this issue). I can try to deal with it but it will always be at the back of my head so I want to, if possible, obtain an exchange within my 2 week free returns period. Hence I am now wondering is there anything I can do to protect myself in case I return the device and they deem it is not a manufacturer's defect or worse, not sending my device back at all like for some customers have had before? They do have a Sydney presence but I believe my payment was to an entity in Hong Kong. I paid for the device through their AU website with Paypal in AUD.

Keen to hear your thoughts on this.

UPDATE (27/06/2020): Everything went better than I or anyone here could've expected. Their policy allowed for a free exchange/refund if the issue was reported within 14 days of receiving the goods. I did so but wanted to see if software updates released by OnePlus would fix it and T Dimension was very understanding and allowed me to return the device over 3 weeks after I have received it. The return process was painless and it arrived in their warehouse within 2 days when I was told it will be passed on to the technical team for checking. One week after I asked for an update and that afternoon itself I was told that the technical team deemed that I am entitled to a refund and that one would be issued to me and would take around 2 business days to process. Sure enough 2 business days later I received a full refund for my device. Could be a fluke but goes to show that a company like T Dimension does do stuff right at times.