CONTRACT UPGRADED WITHOUT MY KNOWLEDE

I ASKED MY CONTRACT TO BE KEPT ON A MONTH TO MONTH BASIS THE NEXT THING IT WAS CANCELLED A MONTH LATER IT WAS RENEWED WITHOUTH MY KNOWLEDGE I CALLED IN AND I WAS TOLD THAT MY CONTRACT WAS UPGRADED ON AN AIRTIME ONLY CONTRACT I MEAN I NEVER ASKED FOR AN UPGRADE AND WHY SHOULD I PAY R400 FOR R200 AIRTIME LIKE IT DOES NOT MAKE SENSE I CALL IN EVERYWEEK AND EVERYTIME I GET A REFERENCE WHICH IS NOT HELPING AT ALL I AM SO SICK OF MTN AND THE CONSULTANTS WHO DONT KNOW THEIR JOB I WANT THIS CONTRACT CANCELLED IMMEDIATELY AND MY NUMBER MIGRATED TO PREPAID ASAP I WOULD NOT RECCOMEND ANYONE TO TAKE A CONTRACT WITH MTN