How to refund my money if I have not availed the services

My daughter had enrolled for the 4 year Class room program - Weekend contact classes in 2015 when she was in 9th class with an option to exit at the end of 2 years, ie. after 10th Class. Per the agreement the exit option should be exercised on or before 28 Sept. 2016. The fee for the entire 4 year program was given as Post Dated Cheques at the time of admission, I could not recollect the exit date as it was signed 2 years back and there was no reminder from FIITJEE also to check if I want to use the Exit option. When I approached FIITJEE during Oct, 2016, they informed me that the exit option due date is already over and therefore you ward has to continue the course. They told me that one of the option is to stop the Post Dated Cheques. Therefore, I stopped all the cheques. Accordingly, she stopped going to the classes and there was no follow up from FIITJEE as well. However, one of the cheque dated 10 Dec 2017 was not stopped and they have encashed the same on 13th Dec. 2017.