Hi, I’ve been having problems with getting vodacom to stop debting my account as my contract with them ended however they never stop

Hi, I’ve been having problems with getting vodacom to stop debting my account as my contract with them ended however they never stop. I’m currently unemployed and yet they keep taking the little that I have every month, I tried contacting their customer service and no one seem to care, what does one have to do to get this sorted.