I'm going to nitpick in reverse.
You are being _charged_
- This is a charge against your card
- They are not a bank, so the money in your "account" with them is just an unsecured, general liability to you. If they go bust, they owe you money but you will never see it.
- If you want to withdraw that money from your "account" and they refuse, then your options are pretty limited.
Once they take it from your payment method, it becomes their money, not yours. That's a charge.