Telkom Unauthorised D.O

My daughters took out contract in 2014 with Telkom. These contracts have expired in 2016 and was cancelled as requested. Lately, Telkom stared debiting one of my daughter's accounts and after 2 visits and being rude, they stopped it BUT NOW THEY STARTED TAKING MONEY FROM MY OTHER DAUGHTER. She is trying to get them to stop but as usual... no can do... Telkom is taking money without a signed debit order, 2 years after the contract expired and was cancelled. How in the world do they do that? And to go and speak to someone at the shop, is useless...they give you a ref number but next month another debit order runs. Telkom, you need to stop... you are hurting your long standing good name.