Cellphone cannot be used since Purchased

DURING APRIL 2014 I PURCHASED A CONTRACT WITH MTN. THE PHONE WAS IN USE UNTIL OCTOBER 2014 WHEN IT STOPPED WORKING. I SPOKE TO SAMSUNG AND THEY TOLD ME THAT THE PHONE WAS BLACKLISTED. I CONTACTED MTN TO UNDO THE BLACKLISTING WITH ALL THEIR REQUIREMENTS SENT TO THEM FOR REMOVING THE BLACKLISTING. TO DATE MTN HAS NOT RESOLVED THE ISSUE EVEN AFTER CONTACTING THEM ON SEVERAL OCCASIONS. MY DATA AND AIRTIME IS BEING FORFEITED BECAUSE THE PHONE CANNOT BE USED TO DATE.<br> <br> PLEASE MTN RESOLVE THE ISSUE, THE NO IS ***