MRP Mobile is the worst

I am actually not a fan of the network and was told I would be able to cancel my contract after a month of the service (this was in March), I have not really enjoyed the service and on top of that I find that the agreed amount over the phone was R100 free and then thereafter R100, but on my statement it says R129. On top of all of this I cannot seem to find any information anywhere (but was told over the phone that all the information I need will be readily available) about how to cancel and have this taken off my account