Hi budakcantik,
Thanks for the post in Apple Support Communities. I understand you have a concern about your iCloud Storage billing, and I'll be happy to take a look with you.
You mentioned changing your payment method from a UK-based card to one based in Malaysia. Did you also change your iTunes Store region accordingly? Check out this information, from the resource titled Change your Apple ID country or region:
- Spend any store credit remaining on your Apple ID. You must also wait for any pending store credit refunds to process before you can change your country or region. Learn what to do if your remaining store credit is less than the cost of a single item.
- Cancel any subscriptions, including Apple Music, and wait until the end of the subscription period to change your country or region. You'll also have to wait for any memberships, pre-orders, iTunes movie rentals, or Season Passes to complete.
- Have a payment method for your new country or region on hand. For example, German credit cards can be used to buy content from only the German App Store, iTunes Store, or Apple Books.
- Back up your iPhone, iPad, or iPod touch to iTunes. You might need to temporarily downgrade your iCloud storage until you switch to the new country or region. You won't lose any iCloud data in the process. After you change your account to a new country or region, re-enroll in a new storage plan to continue using iCloud storage."
If everything checks out there, the information in this link may be useful as well: If your payment method is declined in the App Store or iTunes Store
If you're not able to update your iCloud Storage billing information after you've checked all of the information provided above, I recommend contacting Apple directly: Contact Apple Support
Cheers.