I'm really dissapointed and ****ed off with mtn

From mtn store in vaalmall to mtn call center consults ... Iv been sending emails to their legal teams with no help... They saying I'm owing alot of money and no one is explaining where it's coming from... From last year iv been going up and down with them... I'm really dissapointed by their poor service... Today the call center agent even laughed @me....this people are unprofessional...