Porting without my permission

On Monday I noticed that my telkom number cannot receive sms or calls,I called the call centre 8 times and they could not assist me,I then went into a telkom store today to find out what's happening and I was told that my number has been ported to MTN,how could that be if I did not request any port, I am so frustrated as I need my number to be working as clients cannot get hold of me,this is really pathetic!!! Could you please resolve this issue.