I'd treat this like one of those "pay us in gift card" scams, and get the bank involved.
If they cannot/will not provide the contract terms, then there's no way this is valid. I would start with your parents' bank, see if they have a fraud or consumer advocacy group. Ask about your options for a chargeback or a stop payment. I would strongly reccomend you go in person to a bank location to run this down so you can just lay out the situation to a human being rather than trying to find the right resources yourself from the outside. It will likely take multiple in person trips.
It may also legitimately be cheaper to hire some legal services (a lawyer) to fight this for you, if you're looking at 4 years worth of charge for cancellation.