No update on my credit report, no reply to transunion

My credit score went from 800 to almost 500's due to telkom. Transunion said they were supposed to reply within 20 days but no reply from telkom. They were not updating my credit report which made it seem like i was not paying them, i called and emailed with no assistance which made credit providers do queries which were rejected and score went down more and more. I cannot apply for any credit due to tihs. So frustrated no sure if i should contact lawyers or where to report this as it is ruining my life.