Telkom has no email to contact them and on the phone they bleed you for more of your details ending with we are now off line. detail

I have a contract with Telkom fiber and land line. For about a year all went OK. Suddenly I received an account which shows exorbitant "Subscription services".Contacted Telkom and was told that they have under-invoiced me for many months. So their incompetence is now my fault. I paid every month the invoice in full and on time. The guy on the line gave me eventually a ref No. and said that I will hear from them within 14 days. Nothing happened expect lots of SMS harassment. They have no e-mail address, all is a talk on the phone and nothing in writing. I tried their Chat line. Four times I was interrupted by their advertising and on the fifth the chat said that they are now offline.