Urgent cancell of landline

My mother is deceased. I did send 2 emails on telkoms website to phone me regarding the landline that needed to be cancelled as the person who was billed for this passed away. No response whatsoever and another family will be moving into the house which mean that they can use the line free of charge and I will have to pay the bill which I will not do!! If Telkom does mot respond then they must send that bill to heaven for the deceased to pay.