It is understandably frustrating to see your GCash balance deducted without seeing the corresponding increase in your iCloud storage, especially after paying for the 2TB upgrade. This situation is a relatively common "syncing" issue that occurs when users in the Philippines upgrade their storage tiers in quick succession. Because you moved from the 200GB plan to the 2TB plan almost immediately, Apple’s internal billing system may still be processing the initial transaction. It can sometimes take 24 to 48 hours for the system to fully provision the new space across all of Apple's servers, even if the payment itself has already been confirmed by your e-wallet.
In many cases, the 200GB display is simply a cached status on your iPhone rather than a reflection of your actual account state. To force your device to refresh its connection with Apple's billing servers, you can try signing out of "Media & Purchases" within your Apple Account settings and then signing back in. You should also log in to the iCloud website via a web browser; if the website shows 2TB while your phone still shows 200GB, you have confirmed that the upgrade was successful and your device just needs a bit of time—or a full restart—to catch up.
You should also verify the status of the transaction within your App Store purchase history. Since you made two separate payments, one of them might be marked as "Pending," which indicates that Apple has not yet fully captured the funds from GCash. If the transaction is listed as successful but your storage remains at 200GB after 48 hours, you should contact Apple Support directly. They can manually trigger the storage update if you provide them with the GCash reference number, or they can clarify if the second payment was actually processed as a pro-rated upgrade rather than a full second charge.
If Apple confirms that they have no record of the 599 PHP payment despite your GCash deduction, your next step would be to file a ticket with the GCash Help Center for a "deducted but unsuccessful transaction." They typically investigate these payment loops and issue a refund to your wallet within a few business days. In the meantime, keep your GCash receipts handy as proof of the double deduction.