wrongfully debiting of account

I received relief payment from Westbank between April to June 2020, it was authorised by Westbank as I received an email from them, however, they debited my account on the 26/06 which was *******, when requesting a refund they inform me that I have no relief payment and Westbank is constantly sending me messages on my cellphone suggesting that my account is not paid even though they agreed on my relief payment, Westbank service is pathetic and this bank needs to be investigated for *******ly debiting peoples account.