Incorrect Upgrade --> Ridiculous billing

Hi, in 2015 I upgraded my existing 2GB data contract to the same contract (or I though so). I did the upgrade over the Online channel and it failed, this resulted in an agent calling me and the upgrade was completed by the agent. Never was I informed the the new contract will be an open line contract, resulting in Data bills of R4000 for Nov. This is completely unacceptable and needs to be fix. I want my old contract which is not open line once my 2GB has ran out. Secondly I want a refund for the data charges, as I was never aware of this change and was never informed of the out of bundle rates. I already logged a request with the service desk but this was closed without even given feedback to me, reference number: ***. The number is ***. <br> <br> I am really thinking about moving to another provider, reason being my issue, double debiting subscribers, very bad service desk experience etc.