Telkom mobile downgraded my package without consent

I've been on 20 gigs anytime and 20 gigs night time Telkom mobile package for a few years now. A few weeks back a agent phoned me and off red me a upgrade, I would receive more data but would pay less. I stipulated multiple times on the call that I want my same amount of data, otherwise i am not interested. Now my package has been downgraded to 10 gigs anytime and 10 gigs night time data.When inquiring about this ideas told that Telkom and its agents would never offer customers downgrade in their contracts...but I here I sit with a downgraded package that I did not give consent for. I was told to e-mail *** about this but they have not responded to any of my emails

It's clear I've been misled by the agent who phoned me so he can capture a deal for himself, this is ********* and now Telkom doesn't seem to want to rectify this situation