Answer
Flexischools App (also applicable to CDFpay app)
Firstly, press the Wallet icon. Following this, press on the green TOP UP button.
Press the Edit text at the top right of your screen to remove a payment method. Use the Choose another way to pay text to add a new payment method.
Please note that this will not affect the current balance of your account.
You will be required to add a new payment method in advance of topping up your account again.
Flexischools Website (Desktop)
Select Top Up Wallet on the left-hand side of the screen.
Click the Edit text at the top right of your screen, then press the red cross to remove this payment method. Please ensure to press the red Delete button to finalise your changes.
Please note that this will not affect the current balance of your account.
You will be required to add a new payment method in advance of topping up your account again.