Dear Roblox Team,
So, to keep everything as simple and clear as possible, When trying to buy the Roblox Premium Subscription on the UWP (Universal Windows Program) Version of Roblox (from the Microsoft Store), a blank page appears, hence it is impossible to buy Roblox Premium.
Here is a video that describes everything I’ve said:
Expected behavior
The expected behavior should be that the Microsoft Pay interface actually works, as shown there in 2 old videos I made 2 years ago (watch at the given timestamp):