The Poste Pay circuit is accepted only by PayPal.
So if you want to pay with a Poste Pay prepaid card, when choosing the type of payment, choose PAYPAL, even if you don't have a PayPal account, you can pay with your card, without having to register.
If you have difficulty, you can also call me on 3294250285 and give me the number and deadline on the phone and I'll take the payment with our physical POS.