INCORRECT DATA PACKAGE

I opened a sim card data only contract about 2 months ago. It was a double deal contract where I would receive 6 gigs night time data and 6 gigs day time data for R149 pm. For the past 2 months I have only been receiving 6 gigs night time data and only 3 GIGS day time data instead of 6 gigs. I have made enquiries with the call centre and even in-store consultants as well. It has been a back and forth thing as everytime they log a request to correct the error and I would receive an SMS to say that it has been corrected but effectively nothing has been corrected. The call centre has been telling me that it will be corrected in 24 hours, thereafter 48 hours, 72 hours and so forth. Then I was told that it will only be corrected the 11th of May due to invoicing purposes. I therefore waited - I received my data yesterday and it is still the incorrect package. I have been a customer of MTN for a really long time (years) and I am disgusted at the service that I am getting. I am paying for a full package but instead I have been issued with incorrect deals. I am destined to receive 9 gigs of day time data this month and not 3 gigs as this would make up for last months incorrect package. I hope that this gets resolved as I am on the verge of cancelling my contract. This is the last time that I am querying this as this is unnecessary for me to deal with and I hope that the correct package will be issued to me going forward.