Ya ~ that is the challenge ... if the contact does not specifically say that the Security deposit given is non refundable and must be used for the last two weeks of care than you do have a case to say 'thank you but we do not need require care for the two weeks notice in this scenario and we will just be done and request your security deposit be refunded ... if she does not than I would try the cancel the cheque route with the bank and explain your situation but if she's already cashed it on you and refuses to refund it your option is to either accept care during that time frame to get your monies worth OR suck it up and not to send him and try the Small Claims court to get your $400 back assuming that 200 of that 600 was for the care last week but there is a risk that the court could side with her although given what you've shared the ambiguity of her contract could air in your favor since that is the way the law works ... if there is a reasonable way to interpret it differently than the person who did not 'draft' the contract gets the benefit of the doubt in interpretation in the courts?