PATHTIC, NON EXISTANT SERVICE

I am being charged almost R1000 a month for a contracts I am supposed to being R300 for (R639 in Feb and R919 in March 22). I have been trying to make contact with mtn for the past 3 weeks including Team manager Nadia Allie, however to date no feedback. Not one person can tell me why I am Paying so much for this contract, they even referred me to Mondo, however when I called Mondo, they said my contract is with MTN directly. I need feedback urgently, please do not debit my account again in April with these exorbitant amounts. Please call me URGENTLY