Help- sudden death

We brought this beautiful baby home today- around 12pm. She started to appear timid/afraid so we settled her in her new cage and let her rest. Checking on her regularly. She was sleepy- slept a lot. In the evening- I noticed she was having trouble staying on a perch- so made her a small next at the bottom w food and water- but she didn’t seem well by 8pm I was worried bc she declined - but I thought maybe she was just scared - she past at 930. I am so sad and worried- I’ll call store in the morning to let them know. What could have been the issue- was she scared to death :( my heart is breaking