No Data Allocated

I upgraded my contract in November, to a package that includes 100mins/200sms/300mb per month with an additional bonus 500mb data for the first 3 months. To date I have only recieved one 500mb bonus data. I have called in to the call centre on numerous times and all they say is there is a technical fault. I have been without data now since the 14th of the month. I called again this morning to be told that it is been seen to. I think this is terrible service and I believe that you are in breach of contract. I request a cancellation of this agreement without any penalties!