No delivery after a month

Bought a bed from OK furniture kempton Square on the 29th of November 2019 and to date it has not been delivered! Everytime we enquire they keep on saying it is out of stock and even suggested that we add R390 so we can get a different bed. How on earth do you sell stock you dont have? My sister is starting a new job and does not have a bed to sleep on. Can you please have this bed delivered.