Please accept our sincere apologies on behalf of the Narita Airport Rest House for not honoring your confirmed rate.
Booking.com has negotiated with hotel and hotel has come up with solution to offer the below option for your reservation :

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Option 1 : JPY4,200 per night per room with original cancel/deposit policy
• Free cancellation up to 1 day prior to arrival, and no deposit is required.

Option 2 : JPY1,100 per night per room with full deposit/ non-refundable policy. Also no name change will be allowed.
• 100% deposit will be charged upon confirmation to credit card, and no refund in case of modification or cancellation. Guest name cannot be different from original reservation. Hotel needs passport check upon check in.

If you do not agree neither option 1 or 2, please let us know your preferable condition so that Booking.com to negotiate with hotelier.