Lay buy only to be told after full payment that they don't have the Item anymore

I laybuy a fridge at Joshua door in cosmo city early this year, I have been paying them and now that I have paid in full they tell me they no longer have the fridge and they will refund me or I must buy something else I mean where is the professionalism on that , They are at fault but instead of helping they don't seem to care am very disappointed . We entered into an agreement I mean if they decided to stop selling the fridge the responsible thing would have been to let us know in time so that we can look else where but instead they were reminding us every month to make sure where pay