disgusted with multichoice service

I m so furious with the service of multichoice. I keep on telling them to remove the other decoder from my name that I m no longer using but they keep on lying to me n when the bill comes I must pay way too much. The following decoders are linked to your account:

1. Decoder with Smartcard ***** and Serial Number *V**** 2. Decoder with Smartcard ***** and Serial Number *U**** the second decoder should not be under my name. But still it’s shows everytime I contact their consultant they tell me it’s out. Please help me solve these.