Dwarf Gourami Female

I purchased a dwarf gourami female on October 3 and she had died by the evening of October 7. All of the other fish and cherry shrimp I purchased at the same time are doing great. Water chemistry was fine. Temperature was perfect. I contacted the store several times via email and tried to call them on the phone to let them know about it. I just simply wanted them to replace the fish that had died. Have not heard anything from the store.