Bank failing me

As my bank im disputing a card payment that Rain did on my account which im saying its incorrect but ABSA wants proof . dealing with rain which you hardly ever get any explanations on bills i have to wait for ABSA to investigate what Rain is saying? Sent an email to ABSA on the 11th April no one responded after speaking to the ***** department. now the email wasn't received need to resend it. now the agent Jabusile told me that this might not work as ABSA requires proof that i cancelled by email.