MTN QUERY

I have two phones, *** and *** contracts. End of February, I got a phone call to upgrade which I did. Previously my contracts were R129.00 each on the two phones. So, I upgraded *** to a 20G R169.00 contract and *** to an R99.00 contract. I changed my mind and because I have 7 days to do that, I went to the local MTN outlet and changed *** also to a 20G R199.00 contract. Now I get my bill and it is R1040.66 which is impossible. I phoned this morning to get a detailed invoice but only got a statement. I want to know how you got to the R1040.66 amount. It should only be R368.00 plus the upgrade fee which, if I remember correctly is R150.00 each. And I paid extra last month, so my account should be only maxed R668.00 The lady on the phone said it is partial payment for the old contracts which does not make sense to me. The upgrade was due in March and I did it end of February/1 March. Can you kindly explain these excessive charges to me? I already phoned twice and sent e-mails but no response,