Unable to use Payeasy for JLPT payment

Anyone else with this issue? When I try in internet banking it doesn't recognise the Payeasy code, when I tried ar Lawson it doesn't recognise the customer number. I can't change the payment method.

I can't even cancel my application and start again!

edit: It also didn't work at Familymart, but a friend with a different bank was able to pay it for me. If you have Paypay銀行 it seems like you can pay for this, so just leaving the post in case someone else has this problem in future!