refund me please

I am writing to formally raise a complaint regarding a double charge for a booking made via Booking.com on 30 April for accommodation on 1 May. Despite this being a single room booking, two transactions were processed against my account. I have made numerous attempts to resolve this matter with both the guest house and Booking.com, however I am repeatedly being referred back and forth without any resolution. This lack of accountability is unacceptable, especially given the urgency of the matter. I require the duplicate charge to be refunded without further delay. Please treat this as urgent and confirm:

The reason for the duplicate charge, and When the refund will be processed.