What laptop, and what version of Windows? I certainly don’t get this on my Dell XPS 15 running Windows 10.
So it’s probably something your laptop is doing; is it an HP one by any chance?
I Googled for the general issue; there are reports of it all over, but none specifically on Now, except yours.
So I suggest you first try a Restart on the laptop; and if that doesn’t fix it, Google for the issue likewise, perhaps mentioning at least the make of your laptop, and see if any of the fix advice works for you.
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.