I emailed them about the order I paid 14 days ago, and they say that one of the items that was supposed to be there 19th September (over a month before I placed my order), hasn't arrived yet, so the entire order was being held like a pre-order.

So just how long were they going sit on my order without telling me? Because they said that they don't even know if or when that item is arriving.
If an item is listed on the website as arriving 5 weeks ago, but hasn't, surely an email to inform the customer of that, would be the right thing to do - to see if I'm wanting to wait for however long it takes for that item to arrive, have the in-stock items sent now, or have a refund.
The orders still have to be picked and packed by *people*, so someone should have seen that an item on my invoice/packing slip, that actually says it was in-stock since Sept 19, was not there... and asked about it.
Just like pre-order items, I would split up my orders if I know one item is not yet there and wanted the in-stock items now.

Definitely not happy with their non-existant customer service. Might have to start shopping around for other HK online toy options.
(and they keep asking/begging on their EMS-shipping emails to rate their service on a third party site - they should look at this feedback topic if they want to see what their service is like)