Refund / over charge

During the first week of February 2021, I cancelled my rain sim card online. However, on the 3rd of March 2021 Rain debited my account for the cancelled sim. I tried reversing this transaction via the app and bank with no joy. I called their center on the 5th of March 2021 and was issued with a reference number. I am still following up on this mater with no Joy.