phone number being used by someone else

<p>i am very disappinted with mtn as my number that i was using last week and for the past ten years just stopped working and is now being used by someone else .How is that possible i pay my contract on time and despite them refusing to fix my contract phone that i pay R700 rands for i still pay .I have been paying for a phone that i only used for 3 months and now someone is using my number .This is a total ******* as is not fair as now my whatsapp is off and belonging to someone else .i called in today and they said they will get hold of the legal department but i have been waiting since morning .How long do i have to wait .</p> <p> </p> <p>very unhappy client </p>