Rent to own Car instalment contract

Good day Sir/Madam

on the 18th of October 2017 i signed an agreement of a rent to own Car with Executive motors in Bloemfontein i had my own 2012 Opel Corsa which i traded in with. they bought my car with R86000, i then deposited the their car with R50000 and the installment was R9000 including their insurance for the rent to own car. i then called them on the 25th of November telling them that i do not have money for my first instalment things didnt go as i planned, they then said on the 15th of December they will have to take back their car. i didnt have a problem with them taking their car back but when i asked them what is going to happen to the deposit(R50000) that i payed to them and they said i am getting nothing out of it they dont do refund, now i am left with no car because i traded in my car with them and i am sure they sold it with bigger amount than the R86000 that they offered me and now they dont even want to refund me something from the R50000 that i have paid to deposit the car

please help me to get my money back