A legally binding contract makes the both the buyer and seller to fulfill obligation.BOth landlord and martial art coach are sellers with some similarity. The difference is that the coach collect annual fee while landlord collects monthly rent. The buyers are obligated to pay for the remaining balance whether or not they continue use the service for the remaining term of contract.
However it's hard to enforce in the reality without a legal process.As result, what has been paid is not refundable. What's owed is wiped out unless the buyer is willing to pay. In the case of monthly payment mentioned above, if the parent refuses to pay the coach, the coach will unlikely take any action. The parent pays just maintain a good relationship.
In rental business, there is no need to maintain "good relationship" since you will unlikely come cross each other again. The business relationship is over. You just try to get out the best you can.
One thing you can do is to tell your tenant that you will report breaching contract to any tenant screen network or credit bureau. If they care about their credit, they may cooperate with you. Other than that you can't do much to enforce the contract without a legal process which may not be worthwhile.
The best thing to do is to end this lease peacefully and get the property back in good condition to minimize the loss on damage and renovation.
