TELKOM not cancelling accounts and handing over paid up accounts to attourneys.

My mother has been handed over to attorneys for the payment of a Telkom account that has been cancelled and paid in full. The line was cancelled by sending a official Telkom document, provided by Telkom, in September 2017. She is no longer living in South Africa and has not been there since September 2017. The last payment for the account was made in October 2017. TELKOM does not have an option to send an email without having a contact number in South Africa. To phone will be expensive as my mother is a pensioner and cannot afford to pay for international phone calls. How can we resolve this issue, as my mother does not need to pay for this as she did everything correctly?