It is typical of Eugenia to act as such when the soil is too dry, wet soil, cold air and lack of light. It is also possible that the plant was not receiving the best of care and just slowly deteriorated. Keep the plant in a good light location away from cold and heat source, provide high humidity and most importantly water well then let the soil partly dry out between watering. If the plant's root system is still healthy it should recover in a timely manner. Good luck!
Supannee