RCS refund - not paying me back but take my money very quickly.

Paid my account twice due to the Makro self service app having an error. sent my ID and what happened as per the RCS call center agent. No reply since Wednesday the 6th of August, payment was done on the 30th of July. Called again, and Porche the call agent said they can see my double payment and refunds did reply, they didnt. She has resent it to me which was over 10 min ago and i still dont have it. The email said i must prove i paid them with my personal bank statements, even though she can see i paid them twice. I refuse to share my personal bank statements when RCS already said they have my money and see a double payment from my account. I want my 2nd payment returned to me.