Review Layby refund

I did a laybye some time ago and I paid R4000 deposit. Unfortunately a lot happened and I couldn't keep up with the payments. I went to the shop in July to request a refund, they told me to bring an original receipt and documents and my bank statement. Today I went back to the shop with all the required documents including the receipt and when I arrived there they told me that they won't refund me because the laybye has already expired and I won't receive any money. Honestly I find this hard to accept, R4000 is a lot of money to lose especially since I still have all the documents. How is this possible? Is there anyone else who can assist me please because I'm not prepared to lose so much money. I know I made a mistake by not taking out the laybuy but R4000 is also a lot of money to lose.