Incorrect suspension of landline.

I would like to complain about the service at TELKOM. They suspended my mom's (83 years old) landline while she has a CREDIT of R1095.77 on her account ! I tried to contact Telkom at the following numbers without any success. Nobody answers. 10210, 10213, ***, ***, College Square, Bloemfontein Branch as well as Loch Logan Branch, Bloemfontein. I logged a complaint on their website only to be told that there is a technical error. This is my moms only means of communication. It is essential that she has access to her telephone. I have never experienced such unacceptable service. Can anyone please assist? This is urgent!