@WayneC75
Contact NOW using their live web chat service by clicking on the green chat online button towards the top of this link page, and ask them to investigate what is going wrong here for you:-
https://help.nowtv.com/article/how-to-submit-a-complaint
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.