VODACOM USELESS AT CANCELLING

Vodacom is the most useless company to try and cancel a monthly contract with once the contract has expired.My mother ( now in frailcare and not handling her affairs) had a modem contract for data which came to an end.We went down to the Vodacom shop twice - paid any arrears and they told us how to proceed.I e-mailed collections and they receipted the arrears. Then there were countless e-mails ( with all the documents , power of attorney etc ) to numerous people to cancel the contract.When you telephone they say " send to this supervisor " or " send to cancellations " NOTHING HAPPENS.Then when you telephone they say the number is back in the system???Now they are trying to speak to my mother again and keep calling my phone.I AM VERY FED UP!!!