Unable To Renew Subscription.

[Enkidoh]

You can get the EU time cards from SE's own website (not the Online Store or Mogstation, the seperate online shop on SE's European site where you can buy games such FFXIV itself and it's expansions - you may have to click the country button down the bottom and change it to Australia though), and pay for them in Australian dollars (assuming you're not using a VPN), but they're quite pricy. The specific page to purchase them in AU dollars is found here.

[Enmak]

You can get the EU time cards from SE's own website (not the Online Store or Mogstation, the seperate online shop on SE's European site where you can buy games such FFXIV itself and it's expansions - you may have to click the country button down the bottom and change it to Australia though), and pay for them in Australian dollars (assuming you're not using a VPN), but they're quite pricy. The specific page to purchase them in AU dollars is found here.

@Enkidoh, IT WORKED!

I had tried this a few times over the past few days while getting errors. The error message said, "An internal error has occured (error code: Mandatory field state not found). Please retry later."

Mandatory field not found? Everything I entered had green ticks next to it. I filled out everything it asked me to. Let me look at this again.
I click edit next to the payment details and notice my post code and phone number are not added to the details. Once I put those in everything went through as expected.

Thank you again, @AngelCheese77, @Lirirawiel, @MilkieTea, @Jeeqbit and @Enkidoh! Your suggestions and helpful advice has got me back in Eorzea.