On March 2024, I canceled my greenlight policy with Old Mutual and the status say it is canceled but they are still deducting the premium till now with no refund they had only refunded me a premium of one month instead of 6 months

On March 2024, I canceled my greenlight policy with Old Mutual and the status say it is canceled but they are still deducting the premium till now with no refund they had only refunded me a premium of one month instead of 6 months. I have sent them an email to report that. They asked for my payslip as proof and I just sent them. And they said they paid me and they are lying there is no refund paid. I have just sent them a bank statement to check since then They are ignoring me.