Chin made her debut on 11 September in the shot put
British teenager Rebecca Chin has been denied a silver Paralympic medal in the women's F37/38 discus competition due to a change in re-classification.
The 16-year-old finished second to China's Mi Na who threw a world record of 33.67m to win in the final round.
Chin had already been re-classified in Beijing, with her F44 being changed to the F38 category for those with mild cerebral palsy.
"I'm obviously disappointed with the outcome," Chin said.
According to ParalympicsGB, they were told that Chin no longer fitted into a recognised International Paralympic Committee class.
I'm obviously disappointed with the outcome, but I'm proud to have represented Great Britain at the Paralympic Games
Tim Jones, ParalympicsGB's athletics team manager, said: "It's been a tough couple of weeks for Becca, who had to undergo a difficult classification process when she first arrived in Beijing.
"The athletics team, together with ParalympicsGB, will now be concentrating on providing Becca with full support through this difficult time."
Chin added: "I did my best and performed as well as I could on the day.
"Considering the circumstances of my preparation due to the classifications I'm pleased with how I've conducted myself throughout this process.
"I'm obviously disappointed with the outcome, but I'm proud to have represented Great Britain at the Paralympic Games."
Chin, from Deganwy, competed in the shot put on Thursday, finishing in 10th place, and her F38 class was confirmed by the judges.
That decision was changed after a protest lodged by the chief classifier following Sunday's discus final.
Chin's team-mate Beverley Jones, who finished eighth, said: "I hoped for a bit more today. But I threw OK so I'm quite pleased."