MTN wont change my contract to what I signed for

Signed a new contract with MTN for a 350 Top Up account, but they loaded a normal, as they call it, 350 open account.<br> <br> I have sent them endless e-mails, even sending them copies of the contract that I signed, indicating that it should be a top up contract. I work out of the country and need to be able to control my spending.<br> <br> Thus far the service from MTN has been horrible to say the least and no one is doing anything to help me or fix their mistake. It is strange how they are very quick to approve and take your money, but when it comes to fixing their own mistake, there is absolutely no sense of urgency from them.