Vodacom contract bill

I received call from vodacom early January regardind the data contract,which they said its a router,but on delivery it was a sim data contract,I called them and tell them i dont want a sim I want a router please cancell the contract,the give me this number to call *** then I call them they said its cancelld and give me the Ref 1.***.

And every month vodacom will debit R235 and i will revers it and they will keep on calling me and I will tell them i have cancelled the contract but they are busy doing the same thing every month.