"After reviewing the screenshots, I can advise the 3rd party website does not show booking in the local currency XXX and the rate is prepaid rate while your confirmed booking with Hilton is under credit card guarantee (pay upon arrival rate). For future claim, please specify the name for the 3rd party website that you can make a booking with. We do not review a search engine that shows other websites.

Our decision to decline your claim still stands.

We value your business and hope that this decision does not affect your overall view of Hilton. We know that you have many options when traveling and we look forward to being there to serve your future travel needs.

Thank you."

I don't see anything about having to be in the same currency, and the rate is refundable as most OTA are doing it this way. Basically with what they said it's not possible to do any BRG.