HTC now denying discolouration issue

This post is relating to my earlier post, made here

Despite being sent pictures of my device, HTC have responded saying there is no design fault, and discolouration is due to "user mis-use", in that, I should be using a case, or not carrying my phone in my pocket. (
Red 8X) - "Corners of my red HTC 8X are turning black"
" "
(Red 8X) – "I have a red 8X as well, and the corners are starting to bother me" " "
(Blue 8X) – "I have the blue one...same problem"
(Blue 8X) - "I have a Blue HTC 8X and I've noticed after a week the corners of the phone are really dirty and it's only been in my pockets. It's not like I have dirty pockets but the corners (all four) have started to stain black/dirty"
" " (Yellow 8X) –"Hmm, I noticed this on the yellow display model at AT&T but assumed it was just since so many people handled that"
" "(Blue 8X) - "Yep I am getting these marks aswell"
" " (Blue 8X) – "Yes! I've had my Blue 8X for about a week and a half and all the corners have turned black. I hardly keep it in my pocket either - I hope it's not the colour wearing off!"
" " (8X) –"I sent my phone back to the retailer to get a Black replacement"
" " (Blue 8X) - "I bought the Blue 8X because every phone I've owned has been black and I wanted to have something different, I guess this has been a lesson learnt!"
" " (8X) "This thing picks up dirt like CRAZY. Its the soft plastic skin. Thats why im making my own case"
" " (8X) "I have 2, both the same, all 4 corners discolouring" (I’ve been careful not to post duplicate complaints) – (Blue 8X) "Worn Edges"
" " (Red 8X) – "Red 8X, hardware revision 002. Corners are turning black after about three weeks of ownership"
" " (Blue 8X) – "I have a Blue 8x Revision number 0002 for about 3 weeks now, black corners and edge near the volume rocker."
" " (Red 8X) – "I have a Red Verizon 8X, worn bottom corners"
" " (Blue 8X) – "Rev 0002 blue OEM (from Clove) - all four corners are black and some slight discolouration on the back. It's such a shame :(" (2nd Blue 8X) – "2nd blue 8X and starting to get the dark corners"
" " (Blue 8X) – "Having light fade issues on all 4 corners... Argh"
" " (Blue 8X) – "Blue 0002 on Verizon. Some discoloration on the corners. Had it about a month, and I don't carry it in my pocket"
" " (Blue 8X) – "Revision 0002 on Verizon, blue...Discoloration on corners and on the back" (Yet more complaints and owners) (Yet more, including pictures) (Yet more complaints, including pictures)