False marketing and customer exploitation

The store made us laybye a laptop during December 2017 with a R1000 deposit. We settled the laybye some time during April 2018. Instead of us getting a laptop we told it has been sold and told to wait for a week until they receive new stock. Next thing they called us to come and fetch our refund or rather we should wait for the May month to get a new laptop.

What is a laybye and what are the laws that govern laybye transactions and how we protected as consumers.

We told to come for a refund for money that has been in their account but the refund does not take the time value of money into consideration.