@Carmy63
Have a look at the rules in Broadband Buddy, and see if any of these explain it; it looks like a watershed thing.
Without knowing what site it is though, we can’t see if the rule is something they are enforcing; though I do understand if you would prefer not to tell us the site name.
Set a Payment PIN on your account so that no-one but you can buy memberships on it.
Check your bank accounts monthly for any other unexpected payments to Now.
That way you can at least nip them in the bud, while you and Now figure out whose fault they are.
