Thank you for the reply!
So I decided to call on Friday to check in the status as they said about a week from the placement on the order I can check in. Client services on the phone transferred me to the store I ordered from (where I paid my deposit) and to my shock an SA at the store said the order was unfulfillable! I was heartbroken and shocked and told him I was willing to wait as I really wanted this piece! He said he could try source one by end of day but if he couldn't I would have to 'reorder' and it would be another 4 weeks wait

At that point I said ok please let me know but deep down I had kinda lost hope and expected nothing, albeit disappointed as paying full deposit still did not guarantee the item at the end.
However a miracle happened and he soon texted me saying he had found one and I could pick it up on the same day! I rushed after work to the store, showed them my pre-order deposit invoice and another SA went to find it in the back, she disappeared for about 10mins and I was nervous wondering what the hold up was and I saw she came out empty handed.. I was so anxious and worried they sold it to someone else! She asked if I got the text to pick up, and I name dropped the SA on the phone who told me he sourced one and showed her our text exchange. She went back and this time she found it, saying because it wasn't boxed she didn't see it initially! I breathed a huge sigh of relief!! What a journey to get this item, so many emotional rollercoasters up to the last minute of me picking up the order!
I was over the moon and asked how they managed to source one when my order was deemed unfulfillable, and they said someone had cancelled their pre-order just after I called. I guess I'm still curious how this pre-order system works as I wasn't sure if I was technically supposed to be next in line to receive the item, and why they even accept pre-orders when it seems like they might not even fulfil them! And what order to they decide on when to 'distribute' the available stock to? Either way, SUPER HAPPY it worked out in the end for me, and goodluck to everyone scoring the HTF items on their wishlist