Unauthorized debited amounts by Zone fitness

I'm currently being deducted for a membership that ended in December 2019. I signed up for two contracts one for my son and myself. But the contract that ended last year I was deducted. I've requested zone fitness for refund but I'm finding any joy. I've written an email to manager of Pretoria branch in town no response. They are unprofessional and dishonest. I have copies that prove the contract was for 12months which I signed for in January 2019.