Samsung Microwave — Refusal to replace control panel

I bought a samsung microwave model GW76NM in 2010. The control panel is not working properly. I asked them to replace it and charge me for it. They refused, saying that they don't have spares for this model. They offer to buy it back for a mere 10% of the price of the oven. They cannot do this only after four years of the product. Microwave ovens last for decades and they cannot refuse to service it after four years.