Telkom Failed to cancel contract

In January my mum and I went to the Telkom Chatsworth branch to cancel my mum's contract as the contract was coming to an end and she didn't wish to renew it. We filled out the paper work and signed all the necessary forms to cancel her contract - the gentleman that processed the application confirmed that the last debit will be on 28 February. However today, three months later we find out that the contract cancellation application was never processed!!! Not only that, my mum's account was debit 4 times the original amount of the contract for the past 2 months. This is unacceptable - I don't see why she must pay over R1000 because your useless employee failed to do his job. We want a full refund or this will be taken further to the Independent Communications Authority of South Africa. I don't know what's more upsetting - Telkom employing *********** people or Telkom blindly robbing people.