Worst company ever

They called me promising that with their device I won’t need to pay showmax, dstv and Netflix. Only to find out after the device was delivered that they were lying. Asked for the device to be collected, they purposely gave a wrong number to their courier service and when they eventually collected it they keep on debiting me even though I never used their device. It’s been three months of to and fro with them. The worst thing they promised me that the contract has been canceled but they are still taking my money. They even keep on changing debit order dates every month for so that they can’t be blocked. Can anyone advise me what to do with this people?