Change of plans without consent.

I am so frustrated with MTN, first changing my plan WITHOUT any authorization from me and then I have made 15 calls this morning, to STILL not having this sorted out, as I keep on being transferred from one department to the next, calls just keep dropping and I am just over this. They migrated and basically "downgraded" my plan without consent, which is contract breach, and I have spent 2 hours now trying to find out why this happened, and just getting nowhere. I am not happy.