Incorrect Billin account

in August 2014 i received the statement stating that i owe R2160 from my data account then i tried to call the call centre several times to request for billing history because i belive that i was overcharged for that month where i was told that mtn does not keep data billing records. As a customer i feel that im fairly treated by MTN and now they need me to pay for things that i dont know. Im begging MTN to investigate my billing before i will take further steps .