harrassment at work for prescribed debts

On 26. August 2015 a man called mr. Van Zyl called my supervisor at work and asked for me he then asked directions to my work post and came to speak about a thruworths acc I then asked him details of account as he couldn't. Give me any answers n spoke about \MY"debt infront of cleaners and work people as I'm on duty and was inable to leave my post without calling for reliever everything was openly spoken infront of my work people I work with Mr Van Zyl said he worked for Ver-Tex hired by thruworths n when I said only thruworths debts I had was long ago n prescribed by now as over 6yrs any contacts calls letters or payments he said he would get back to me n left .. Feeling badly harrassed in work place where obviously this man came to create drama n trouble for me"""