Total Incompetence

I am being harrassed by Nu Debt on behalf of their client Telkom for an alleged debt. They supply their whattsapp number but no one bothers to read your responses. Both entities should employ persons that understand basic accounting principles like the difference between a debit and credit. Surely there must be legislation in place to protect people from having to be subjected to their unsubstantiated demands for debt. Is a debt collecter subject to a code of conduct and subject to cerain rules of an ombudsman.?