Reduction not honored

I cannot get assistance from anyone on the WA chat. They say its the only platform they use, i have provided them with my contact number to call me , yet no one does. I was having difficulty in July to afford my Fibre , so i called in to cancel , they provided me with a reduced rate for a period of 6 months. I accepted and continued my network coverage with them. they have now for the past 2 moths debited me the higher amount. I have the old WA chat screenshots and when i request to speak to someone they refuse to contact me. The deal of the reduced payment according to the previous agent in July said it will be the lower amount till February 2023. Can someone in the accounts department resolve this