I've had similar experience. I'm sure it's fraudulent to take money from someone's account without their knowledge or consent. I've had to email the customer services to discuss this, only to be told via email that I can use the money deducted from my account as 'credit ' to be used for offers and passes. What a ridiculous customer services. No wonder they are not honest enough to ensure that their customer services number is available publicly. I'm not sure if this is helpful but the more you talk about the barbaric business attitude the more the more reasons for NowTv to review their policies.
After reading your post I have come the the conclusion that you have misinterpreted some of Now TV's actions, such as:-
You said, "I'm sure it's fraudulent to take money from someone's account without their knowledge or consent".
You are right in your premise but you have already agreed that Now TV can take money from your account, i.e. when you agreed to the Continuous Payment Authority a.k.a CAP, when you signed up for their service.
Also, since they took that money legitimately they are under no obligation to give you a refund but offering you credit is the next best thing.
However, if you feel that you have been mistreated and deprived of your funds then you have options.