Bad customer service

My cellphone contract ended on 12 August 2021 and Cell C was supposed to pay my refund of R109 but to date I have not received my refund, every time I am being told a different story, first they wanted my bank details which is strange bcoz they have my bank details as they were debiting via debit order however I emailed them but still they have not paid my refund. I regret having a contract with cell C, they give bad customer service and take the customers for granted. I am very unhappy with the poor service that I have received from them.