Cancelled Cellphone Insurance Refund

I have cancelled one of my cellphone insurance in December 2021 and got confirmation from Administration plus but Telkom continued to debit me, May 2022 I went back to the Insurer and they even provided me with an sms confirming my refund but Telkom never updates their details in order to refund me all the money they debited me after contract was cancelled. When I called Telkom , they said I am not due for a refund yet they debit a cancelled service .Telkom has really given me the worst service with this issue.