Sorry, but the ISP are perfectly entitled to continue charging. Your daughter has entered into a contract which states that, for a certain period of time, she'll make regular payments and the ISP will make their service available to her. Whether she chooses to (or is able to) use that service is irrelevant to the contract.
It's the same as if you buy a season ticket to watch your favourite football team. The club will be honouring its side of the contract as long as it keeps your seat available for you to use. If you choose not to watch a particular match (or, say, you're unable to do so because you're in hospital) you've no right to any refund.
Chris