Pushy call centre tactics

I am writing this complaint on behalf of my dad Bert (AC Pretorius). He recently received a call from someone identifying themselves as an employee of Altech Autopage Durban. The person was extremely pushy and kept telling him he would lose his contract if he didn't upgrade. May I add that the call was in English, my dad's THIRD language (He is Dutch) My dad kept saying he didn't want anything and stated no repeatedly, saying he needed time to think. The caller had all my dad's details except for his ID number, and this upset my dad too knowing that someone was calling with all his details over the phone. My dad arrived at our house today to say that he could not make calls but is only able to receive them and we can only assume that the person who called my dad simply changed his contract. Kindly return all of this to the original contract - you have NO RIGHT to make changes when someone says no and does not fully understand what you are trying to do to them !!!!