Bad Customer service

On 6 April 2023 I called Cell C and told the consultant that I wanted to down grade to the lower package to which we agreed that that the package will take effect from 6 April 2023. I also received a contract stating that I will be debited R109 including VAT as from 1 May onwards but to my surprise Cell C has been debiting my account in excess of R199 per month without any explanation whatsoever. Please let me have a refund.