@Anonymous User
Glad you solved your immediate issue; but both apps work perfectly for me, and for me, the one from the Store is greatly to be preferred.
Recently, after another user reported difficulties, I though that maybe the Store version had been changed so it no longer worked or something, so I entirely deleted my Store app, and cleaned up behind it with CCleaner, to ensure it was gone completely.
Then I downloaded it again, signed in, and it was still fine.
So if you can’t run the Store app, then there is still something wrong at your end.
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.
