Unauthorised debits

Multichoice goes into my account each and every month debiting their desired amount of money, i keep reversing and it cost me so much money to do so. I tried canceling the debit order n paying cash but still they debit, this morning they debited 339 my subscription is not even that amount, i paid yesterday at Pepcell 135. I honestly dont know if this is a **** or what it is annoying now. Please return my money in full ASAP. This company is honestly full of ****.