MTN DIRECT MESS

I contacted mtn direct in october 2019 to upgrade one of contracts to a 20gb deal which was a double data deal for R300 pm which means 40gb day and 40gb night now everything was done told by the agent to send documents for approval all was done...so i thought everything was in order now for Dec I saw a message from my bank an amount of R1900+- being debited now i never paid that much to MTN so something must be wrong I didn't check my debits for Oct and Nov which was a mistake ....I opened my MTN app only to find that the migration was never done and im paying for 6 data bundles...to the Amount of R798...so first off all why was the migration never done...I don't know what went wrong but fix it Promptly as im paying for a mistake MTN made.