Bad Service

Hi there... My parents are pensioners and bought a sealy bed at OK Furnitures. Its still under warranty and my dad went to OK to tell them the mattress is faulty, Ok escalated it to Sealy and Sealy said that they dont make those beds anymore. Furthermore, they want my parents (who are pensioners), to pay in a extra amount of more than R1000 for a bed that is still under warranty. Is it my parents' fault that Sealy doesnt make those beds anymore and why must they pay extra money? My dad is fed up with this whole story and doesnt know what to do about the situation anymore.