Yes. And the law would simply state that the customer may not be billed more than that maximum for the service period. Up to the business to restrict their use

Yes. And the law would simply state that the customer may not be billed more than that maximum for the service period. Up to the business to restrict their use of the service, if they want to. If it's really so 'complicated' that that part can't be done, well, I'm sure it would suddenly become a business priority to cut off use when the limit is hit, if the business can't charge for it.