Telkom NGN account charging without notification

We are trying to buy a house, and had our credit scores check only to see we have an account for something called Telkom NGN in arrears from 2018 that has completely destroyed our record, we have received NO accounts for this amount, we did NOT sign up for Telkom NGN and we had no idea we had an account in arrears, it is against the law to keep charging someone for something without notifying them, atleast once a year to renew the account! Trying to talk to telkom customer service you wait for ever costing hundreds in airtime . Worst company ever