The knob on my nautral gas wall heater melted off....

The knob on my nautral gas wall heater melted off. Called customer service to see if I can buy another control knob. They told me they don't make that knob anymore. YET THEY SALE THE SAME UNIT THAT HAS THAT KNOB ON IT. Told me I will have to buy a new unit. I TOLD THEM , I WILL BUY FROM A DIFFERENT COMPANY AND NOT FROM DYNA-GO.