MTN ARE *******

MTN IS THREATENING TO ADD MY NAME NEGATIVELY ON MY CREDIT RECORD. MTN IS CHARGING ME FOR AN UNCAPPED WIFI SERVICE THAT I HAVE CANCELLED AND NOT USING. AS PER THE MONTH TO MONTH UNCAPPED CONTRACT I AM USUALLY CHARGED UPFRONT FOR THE MONTH TO COME BUT I CANCELLED RETURNED THE ROUTER TO THE NEAREST MTN STORE A MONTH BEFORE. IN ADDITION WHEN I SIGNED UP I WAS CHARGED A PRORATA FEE AND AN UPFRONT FEE IN ORDER TO GET CONNECTED. AGAIN MY QUESTION IS WHY CHARGED AGAIN FOR THE MONTH I AM NOT USING AND CANCELLED???????? THEY ARE *****ING MY MONEY AND THIS IS ******* PLAIN AND SIMPLE.