Realflight 95 Serial Number Hot Here

Hello — I purchased RealFlight 9.5 (include edition) on [date] from [vendor]. My serial number: [paste exact serial]. When I attempt to activate/install, I receive an error stating the serial is invalid/locked ("serial number hot"). I have attempted reinstalling, entering the key manually, and installing on another PC. Attached: purchase receipt and screenshots of the error. Please advise next steps or reissue a working serial.