IGNORED!

I took out a new cell phone contract in Feb 20145. My new no used to belong to another person who was no longer with that cellular provider. I have been getting ENDLESS phone calls and sms messages to this person from Std Bank trying to locate him for debt collection. I REFUSE to change my no. I have made about TWENTY calls and sent TEN emails to Std Bank telling everyone including their call centre that this no NO LONGER BELONGS TO THEIR CLIENT!!!! NO response and NOTHING has been done!!! How do I get my number REMOVED??? How difficult is it to understand that my number is MINE?????? Every other person or company that has called me looking for this other man has removed the number. WHY CANT STANDARD BANK??? This is RIDICULOUS!