Paying for Smartphone Apps via Phone Company

I tried to upgrade a smartphone app and during payment it gives me the option of using credit card or Changhua (my phone company). I selected pay via phone company.

I tried 3 times over 2 days and received messages 3 times saying Changhua has received the request.

But the app will not go past the free stage into the paying stage.

Does paying by this method work? Has anyone tried? Maybe I need to go to the shop or call them for authorization.

Edit: Received this message translated “ Unavailable service for application category (non-national natural person) [OR-DVASA2-02]”.

I think you need to enable it first.

Here’s the solution.