Newsflash: Appraiser Measured My Home 50 sq ft less than it’s been for the last 20 years.

I purchased my home in 2018 understanding I paid for 1635 sq ft.Our buyers lender hired a guy who measured it 50 sq ft less and refuses to change it after being provided tax information as well as the previous appraisal. The buyer wants us to come down 5k in price as a result. I’d attach the sketches but this sub doesn’t seem to allow it.