Did not get my data topup on my contract

I have a contact with MTN. This contact it a top up contract. On a monthly basis I get 100 minutes and 300MB on the 2nd of every month. I am in month 6 of a 24 month contract and this month MTN decides not to give me my 300MB of data! I only got the 100 minutes. Call the call centre and kept getting cut off when speaking to a consultant. on call 9 i eventually get my issue logged and get told it will take 5 days to resolve. Why must i be inconvenienced further and wait this log to get my data that i am entitled to as per my contract with MTN. why must i spend additional money to buy data when i have a contract with data! It is now the 7th of the month and still not data of feedback. I also messaged MTN on twitter and they as far as getting my ref number to assist, but that only seems to have gone into a cyber black hole! If it is not one thing with MTN it is another. I am tired of the monthly fights!! I want nothing more to do with them!. cant wait for this contract to end so I can port to a network that wants my business and wont try ***** me.