Only Six months of data

This problem started in 2017. Aldo I had a fix monthly contract all of a sudden data as put to my contract and the amount just went from R699 to Over R2000 a month. We did call and every time we call they did pit down the calling on this contract with the data. I did still buy extra data and airtime. this also got accumulated with the billing. In July of 2018 we had to upgrade. I as advised by MNT to pay the bill outstanding of R9600 and upgrade to a new contract. I was talking to MNT Legal and they said that this money will then be shown as a credit on my account. this did not happen an after 1 month of the new contract we again disconnected. MTN legal was contacted and They would have send a letter to MTN that we was not owing, The contract was reconnected and due to the fact that we had a big credit with MTN we were waiting for the billing. For 11 Months we did not hear any thing of them. Then I required om the account. They they suspend it immediately. I struggle to get hold of customer care and there is no way to contact Legal. The person that I talked to at customer care were very arrogant and advice me to pay this account. I explained and she said that there is nothing they can do because they only keep records for 6 Months. I need this phone and there is no answers. Please can some-one help!!!!!!!!!!!!!