Breach of contract

I took out a data contract in March 2019 with mtn (30gb+30gb + 30gb night express+30gb night express) Since then I only receive half of the night express(30gb) They have also reduced the night express hours from midnight to 6:00am to midnight to 5:00am without notifying me, even though those bright champions in the call centre insist that everybody was notified last year. I wasn't. I consider this a breach of contract, yet they still want me to pay over R2400 for early termination, its impossible to get through to their legal department to fight this, so here I am complaining on Hellopeter.