not loading data plan and then charging me

On 1 May 2015 I upgraded my cell phone contact and loaded a 24 hour data bundle in order to set up the phone and get everything the way I wanted it. I recieved an sms saying I have 24 hours to use it. I then proceeded to download etc. A few hours later I recieved an sms saying I had exceeded my credit limit. <br> <br> I immediately called the call centre who logged my complaint and said I must call back in 3 days, which I did. I was then told to call back in 5 days. When I did this again I was told it was not logged correctly and that the money was going to be deducted by I could query it in another 5 days. I have done this and am still waiting for any feedback.I feel it is ridiculous that the last 2 times I have upgraded my contract I am left fitting a huge bill that was not my fault