Not Receiving what was discussed

When I upgraded I was promised to received an additional 500mb of data per month for the full term of my 24 month contract at no extra charge to myself. This has not happened, I have yet to receive this. <br> I have tried to contact them by means of 082111 for 2 days, but I am unable to get through. Day 1 my calls kept being cut and today I was left holding for 30mins.<br> <br> This is unacceptable and would like a response from my service provider on this.