APPLE WALLET

My son had signed up for some creative tool called Crayo.AI on their website. I thought he was signing up for an app through Apple. Well that is not the case. The website for Crayo.AI has no way to contact them and also gives a fake email address that all communication gets returned. Well my son does not have any funds in his Apple Wallet and I cannot put any funds in as they will take it. However, Crayo.AI continues daily, sometimes multiple times a day to withdraw $19. I do not know how to stop it or block it. What can I do?