Charged for data and calls on a top up contract

I upgraded my contact in May/June this year to a top up contract paying a monthly fee of R494, which was correctly debited end of July, then came end of August where I was debited R2034, and on further investigation I was charged for calls and data irrespective of me being on a TOP UP contract. On the 2nd of Sep I called and was assisted by a Grace and she told me MTN was in the wrong and she would log a query on my account so I can be refunded, she gave me a reference number and was told to call back in 48 hours. When I called back on the 4th, my \reference number"did not exist"