OK cannot deliver as the contract stipulates!

My sister Beauty Majova Lay-byed a fridge at Ok Furniture Mount Frere since June 2017, when she wants to release the fridge in December then the store does not have the item! Why would they have a lay-bye option but they cannot deliver as a store? What pains me more is that now they have the full amount with them but no stock. If they cannot give her this fridge then refund her so that she can buy it somewhere, coz if she did not want it she should have not lay-byed it in the 1st place.