It turns out my ebook on kindle is not for sale in the US region (amazon.com), but is available else where such as UK, due to something about tax and copyright.
What a bummer. That explains why my friends has been asking me why they couldn’t purchase my book. You have been trying to support my first book but you were disappointed. I’m so sorry this has happened.
There is a workaround for this issue. We have to change our region by giving an actual address. It seems like changing the site is just not enough.
Do correct me if I’m wrong, since I’m not an expert in this.
Sorry for the inconvenience. I will try to publish my own copy in this website soon to allow my friends here to read my work. You guys back here are still my most important customers, since you all have inspired me to write in the first place. Besides, the paperback and local copies will be available, but will take a long time to reach to you.
In the mean time, let me share the way to bypass the region issue:
First off, when you open the link to purchase my book in amazon.com, it will look like this:

But if you open amazon.co.uk, it will look like this:

Now, to change the region, if you are determined to get your hands on my ebooks- which I deeply appreciate your effort, is to navigate to the highlighted ‘Content and devices‘ link.
Then you will be met with this:

Proceed to click on the Country/Region setting,

Now, this part is tricky, you will need an actual address with proper zipcode. To make things easy, search the map for anywhere in the UK, or use ones you have if your friends or yourselves do live there. Click Update and you are done!
Sorry for my dear Malaysian friends. I will try to look for better ways to bring my work to you. Stay tuned ya!