(I have a Mac, but not a MacBook, and an Epson projector).
What do you mean - sound from AV? is there an output on the MacBook (e.g. Audio Out) where you are trying to play the audio on a third (unspecified) device?
Or are you trying to play it through the (also unspecified) projector?
Is this a setup that works with other Now content, or non-Now content, played from the MacBook?
i.e. have you narrowed the problem down to Now Sports, but other content plays the audio where you want it to (wherever that is)?
With my Epson projector, I feed the source, video and audio, into my soundbar to play the audio and feed the video only onward to the control unit for the Epson.
The Epson can play audio, but it isn’t Home Cinema.
(I also have the option of feeding the video and audio into the control unit, to be split there and sent onward to projector and soundbar respectively, but I don’t do that ).
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.