Monthly payments going on over 3 years

I'm still been debited by ON AIR. It's been more than 3 years now. How expensive can a DSTV fancy decoder be? Just because it can record, fast forward and all that now I must pay for so many years. I just don't understand this at all. DSTV says they not one company and yet this machine does Multichoice work. Please if I can get this matter sorted out I will really appreciate it. ☹️