Refusing to cancel account and billed extra not used services

I cancelled my vodacom account in December 2018. In January I got debited again. Now in February they debited me again after not resolving my previous complaint and charged me for roaming!!!! I have not used roaming!!!!! My roaming was off. I specifically instructed vodacom to stop the account and I switched off roaming on my phone settings. I only used WiFi at the airport and in WiFi spots. I took my SIM card out on the 28th is December. I do not understand how I am billed for roaming when my SIM card is not even in my phone!!!!! Please someone respond to me VIA EMAIL as I’m not in SA. I will be reversing this latest debit order as well. How difficult is it to cancel an account?!?!