Endless cancelation of contract and my account still gets debited

My contract ended and I then cancelled it, I still got debited the following month but i accepted it as it may not have been updated on their system, I then cancelled that same contract more then two times after that and yet I still get debited and to make things worse its a sim I got with the 2nd phone that gets airtime and I never used that sim once, I'm not even sure if I still have that sim, is there any point in phoning and canceling this contract again? I don't even want to get reimbursed would just like to finally be rid of vodacom's ****py service.