Mtn contract failed me

I took out a contract with Mtn in 2018 Dec for 2 headset paying R638, 2019 Nov I was called by one agent from Mtn.

Reason for the call was to change my plan because Mtn was overcharging they clients and majority left now they trying to keep those who r still active. The new plan I was gonna pay R499 for both phones n the will also increase my minutes, data n SMS bundle but only for the main phone.

I took time with that lady because to me it was too good to be true n I made jokes about April fool in Nov and that Christmas came early for me, but she assured me that its Indeed true. I took out the new plan because she said its immediate and R499 will be deducted from end November but instead R618 was deducted until now. I tried to enquire but was told different story, I asked for the recording I am taken from pillar to post. Its now over a month waiting for my recording I am not sure if they trying to edit or what. Please someone out there assist