MTN Agent at fault! Fix your mistake!!!

a week ago and still no reply: "I was given 3 options by the mtn agent telephonically prior to upgrading my contract and I chose the option(R299) with the most data and I was CLEARLY told that I can top up with voice bundles as well. The other option was my 2nd choice with 100 minutes and data for R349. Not even a month into my current contract I'm sent an email stating that voice bundles will no longer be available on my plan! Had I known this I would have taken option 2 that gave me minutes. I call mtn customer service and I'm told that the agent was wrong and should not have done that. Sent them an email as well and no reply. So now what mtn? The client must suffer because of mtn's staff incompetence??? How can you fix this mtn?"