Dstv Multichoice ******** behavior

I cancelled my Dstv Multichioce in 2016 then in the beginning of 2018 they debited R800 from my account so they took my money from my account without my permission or signature so I just cancelled that depit order at my bank because it is ******** behavior, this morning Dstv phoned me and told me I have to pay R500 to them and if I dont they will keep on calling me till I pay. I feel they are ********* to do this and take money without my signature they just do what they want.