mtn fails to resolve query of data

On 02/08/2015 i took out a contract at mtn and im paying R400 per month. When my 1st instalment was due i received an sms saying that i must pay R891.00 when i called to query why i must pay this amount of money i was told that i had unlimited usage of data therefore i was billed for R491. I did not understand but i paid the R891 because my phone number was suspended and i was expecting important calls. Now on the 14/09/2015 i was supposed to receive 300 data, 200 smses and 100 minutes of which i didn't receive the data. I called the call centre on the 17th and they said the matter will be resolved in 7 days. 7 days passed and nothing was resolved. I called them again today to follow up on the matter and i was told that the data was sent to me on the 26/09/2015 and on that day i bought myself 1G of data and so i do not know where is the 300 data that mtn claims to have sent to me. Im very disappointed because they are quick to debit their money but can not resolve my issue. There was not even a notification by sms saying that the data was sent to me. **************** at its best. Please help