Wrong package after promises to contact me

I was phoned by an agent and confirmed a 5GB Wifi plan for R99 per month on around 11/12/2015. The next day I was phoned by another Cell C agent which told me about the 20GB Wifi package. I told this agent that I already confirmed to 5GB package and would rather want to change to the 20GB package, she would phone me later. I never received that call. I then received my Wifi modem with the sim card. 04/01/2015 I phoned Cell C to confirm that I was on the 20GB package, they confirmed I was NOT. I asked them about the 20GB package, which I wanted. I havent used any of the Data as I did not want to activate the sim before I was on right package as I asked for. I was transfered from department to department with no success. I was promised to be phoned back before 12:00pm on 2016/01/05, this never happened. I phoned back, yet again being transferred between departments, with no success. I was promised to be phoned back before the end of the day and is still waiting. I asked to speak to a supervisor and after holding for around 15 - 20min my call was dropped. Very upsetting that they will sell you a contract in 15min, but you will go weeks without help regarding your request.