SunDirect DTH — hd set top box non placement to hevc

I preferred hd set top box over sd and bought hd box 3 years ago though it costs more. For the last 2yrs i am viewing sd channels as per assurance of sun direct that i can change/subscribe hd channels at any time.

Today when i contacted for hd channels subscription they told that my hd set box will no longer work. They told me to pay 699+ service charge to get upgraded hevc box. Then i asked "why should i pay, and it's already a hd box. When you upgraded software, you have to replace it with no charge." then they told they replaced it for some customers only. I don't understand this partiality.

When i bought hd set top box for higher price, they ought to replace it.

My sundirect smart card number:
[protected]

Plz help me out.