While there are three ports on the back of a NowTV router, one of them has to be for the incoming signal from the telephone socket on the wall, so you can only connect two wired devices to the router.
Could this be your problem?
However, you should be able to connect a further, larger, number of devices by WiFi.
If this is what makes it cut out, you will need to speak to the NowTV Broadband helpline about this.
Work through the following link until you find the telephone number you should call:-
Get in Touch (all the options, and the best place to start):-
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.