False accusations and threats

My dstv has been off for about two months ,I received a phone call from Multichoice a few days ago saying I need to pay them,i have explained that I have not been using my dstv for quite some time,the person who contacted me insisted that my decoder is active and accussed me of using their service. I then plugged my decoder in again just to make sure ,the very next day I received a sms threatening to take me further .I then decided to phone Multichoice to find out why they SMS,d me. I think its totally disgusting that they accusing me of having the benefits of dstv while I did not at all.

I want answers,because I'm not paying for services I did not use! This is highly upsetting as they are persistent about it. I'm asking that this matter be resolved ASAP.