Annoyed with MTN

MTN as far as I'm concerned deserve a zero on all their surveys. I've had my number er since 2001, been a loyal customer without a contract. Left the country in December for business and advised the call center of it , while requesting International roaming. Then I was advised its done automatically, apon my return now I figured out my number has been given to someone else. After calling the contact Centre every day then to be told my number will be re connected witha new owner which now means his getting all my bank notifications and all other business corispondance. Went to 3 different MTN offices was told to get an affidavit which I did but till today no number and no help just being sent from pillar to post and 20 different answers but no solution. I'm so disappointed in MTN and am afraid to say but thinking of switching to a different service provider.